365 Adjectives That Start with O | List with Definitions and Examples

As you may know, adjectives that start with O are not so plenty as other alphabets, like B, C, S… But still, they are equally important and indispensable in English language.

Adjectives starting with O are used to describe or modify nouns pronouns, making your writing and speaking much more specific, and a lot more interesting. Let’s take a look at some examples including adjectives beginning with O.

  • There is an open suitcase on the ground.
  • My brother and I live on opposite sides of the city.
  • It’s an obvious fact that Jim loves her.
  • This is just an ordinary book.

We can see by adding descriptive words that start with O in above sentences, the messages they convey are immediately clear and specific.

Continue reading to get a full list of adjectives that start with O, as well as definitions and examples.

Adjectives That Start with O – Full List (365 words)

To begin with, I am sharing with you a list of adjectives starting with O. And some of these O adjectives are quite commonly used and helpful in everyday life.

  • Oafish
  • Oaken
  • Oaten
  • Obdurate
  • Obedient
  • Obese
  • Objectionable
  • Objective
  • Oblanceolate
  • Oblate
  • Obligate
  • Obligated
  • Obligational
  • Obligatory
  • Obliging
  • Oblique
  • Obliterable
  • Obliterate
  • Obliterated
  • Oblivious
  • Oblong
  • Obnoxious
  • Obovate
  • Obscene
  • Obscure
  • Obsequious
  • Observable
  • Observant
  • Observational
  • Observing
  • Obsessional
  • Obsessive
  • Obsolescent
  • Obsolete
  • Obstetric
  • Obstetrical
  • Obstinate
  • Obstreperous
  • Obstructed
  • Obstructive
  • Obtainable
  • Obtrusive
  • Obtuse
  • Obvious
  • Occasional
  • Occidental
  • Occipital
  • Occluded
  • Occlusive
  • Occult
  • Occupational
  • Occupied
  • Occurrent
  • Oceangoing
  • Oceanic
  • Ocellated
  • Ocher
  • Ochre
  • Octagonal
  • Octal
  • Octangular
  • Octogenarian
  • Octosyllabic
  • Octuple
  • Ocular
  • Odd
  • Oddish
  • Odiferous
  • Odious
  • Odoriferous
  • Odorless
  • Odorous
  • Odourless
  • Oecumenic
  • Oecumenical
  • Offbeat
  • Offenseless
  • Offensive
  • Offhand
  • Offhanded
  • Official
  • Officious
  • Offish
  • Offshore
  • Offside
  • Offstage
  • Ohmic
  • Oily
  • Old
  • Olden
  • Oldish
  • Oldline
  • Oleaceous
  • Oleaginous
  • Oleophilic
  • Oleophobic
  • Olfactive
  • Olfactory
  • Oligarchic
  • Olive
  • Olivelike
  • Olympian
  • Olympic
  • Omani
  • Ominous
  • Omissible
  • Omissive
  • Omnibus
  • Omnidirectional
  • Omnifarious
  • Omnipotent
  • Omnipresent
  • Omniscient
  • Omnivorous
  • Oncologic
  • Oncoming
  • One
  • Oneiric
  • Onerous
  • Onetime
  • Ongoing
  • Online
  • Only
  • Onomastic
  • Onshore
  • Onside
  • Onstage
  • Ontogenetic
  • Ontological
  • Onymous
  • Oozy
  • Opalescent
  • Opaline
  • Opaque
  • Open
  • Opencast
  • Opencut
  • Openhanded
  • Openhearted
  • Openmouthed
  • Operable
  • Operant
  • Operatic
  • Operating
  • Operational
  • Operative
  • Operculate
  • Operculated
  • Operose
  • Ophthalmic
  • Opinionated
  • Opinionative
  • Opponent
  • Opportune
  • Opportunistic
  • Opposed
  • Opposing
  • Opposite
  • Oppositive
  • Oppressive
  • Opprobrious
  • Optative
  • Optic
  • Optical
  • Optimal
  • Optimistic
  • Optimum
  • Optional
  • Opulent
  • Oracular
  • Oral
  • Orange
  • Orangish
  • Oratorical
  • Orbicular
  • Orbiculate
  • Orbital
  • Orbitual
  • Orchestral
  • Ordained
  • Ordered
  • Orderly
  • Ordinal
  • Ordinary
  • Organic
  • Organicistic
  • Organisational
  • Organised
  • Organismal
  • Organismic
  • Organizational
  • Organized
  • Orgiastic
  • Oriental
  • Orientated
  • Oriented
  • Original
  • Originative
  • Ornamental
  • Ornate
  • Ornery
  • Ornithological
  • Oropharyngeal
  • Orotund
  • Orphaned
  • Orphic
  • Orthodox
  • Orthogonal
  • Orthomolecular
  • Orthopaedic
  • Orthopedic
  • Orthopedical
  • Orthoptic
  • Orthostatic
  • Orthotropous
  • Orwellian
  • Oscine
  • Oscitant
  • Osseous
  • Ossicular
  • Ossiculate
  • Ossiferous
  • Ossified
  • Osteal
  • Ostensible
  • Ostensive
  • Ostentatious
  • Other
  • Otherwise
  • Otherworldly
  • Otic
  • Otiose
  • Ototoxic
  • Ottoman
  • Outback
  • Outboard
  • Outbound
  • Outbred
  • Outcast
  • Outcaste
  • Outclassed
  • Outdated
  • Outdoor
  • Outer
  • Outermost
  • Outflowing
  • Outgoing
  • Outlandish
  • Outlaw
  • Outlawed
  • Outlying
  • Outmoded
  • Outmost
  • Outraged
  • Outrageous
  • Outre
  • Outrigged
  • Outright
  • Outside
  • Outsized
  • Outspoken
  • Outspread
  • Outstanding
  • Outstretched
  • Outward
  • Oval
  • Ovarian
  • Ovate
  • Over
  • Overabundant
  • Overactive
  • Overaged
  • Overaggressive
  • Overall
  • Overambitious
  • Overanxious
  • Overarm
  • Overbearing
  • Overblown
  • Overbold
  • Overburdened
  • Overbusy
  • Overcareful
  • Overcast
  • Overcautious
  • Overconfident
  • Overcooked
  • Overcredulous
  • Overcritical
  • Overcrowded
  • Overcurious
  • Overdelicate
  • Overdressed
  • Overdue
  • Overemotional
  • Overenthusiastic
  • Overexcited
  • Overfamiliar
  • Overfed
  • Overfond
  • Overfull
  • Overgenerous
  • Overgreedy
  • Overgrown
  • Overhand
  • Overhanded
  • Overhasty
  • Overhead
  • Overheated
  • Overindulgent
  • Overjealous
  • Overjoyed
  • Overladen
  • Overland
  • Overlarge
  • Overlying
  • Overmodest
  • Overmuch
  • Overnice
  • Overnight
  • Overoptimistic
  • Overpowering
  • Overpriced
  • Overprotective
  • Overproud
  • Overqualified
  • Overrated
  • Overrefined
  • Overripe
  • Oversea
  • Overseas
  • Oversensitive
  • Overserious
  • Oversewn
  • Oversexed
  • Overshot
  • Oversize
  • Oversized
  • Oversolicitous
  • Overstrung
  • Overstuffed
  • Oversubscribed
  • Oversuspicious
  • Overt
  • Overvaliant
  • Overweening
  • Overweight
  • Overwhelmed
  • Overwhelming
  • Overworked
  • Overwrought
  • Overzealous
  • Oviform
  • Ovine
  • Oviparous
  • Ovoid
  • Ovoviviparous
  • Owing
  • Owlish
  • Own
  • Owned
  • Ownerless
  • Oxidative
  • Oxidised
  • Oxidizable

Adjectives That Start with O – with Definitions and Examples

To know more details about these adjectives beginning with O, check their definitions and examples.

  • Oafish

Definition: rough or clumsy and unintelligent

Example: He called me a stupid, oafish, little girl in front of everyone the night I met him.

  • Oaken

Definition: made of oak wood

Example: The warriors carried huge oaken shields.

  • Oaten

Definition: made of oats or oat straw

Example: The first product was an oaten biscuit, released in 1992.

  • Obdurate

Definition: used to describe a person who refuses to change their mind, or someone or something that is difficult to deal with or change

Example: Several obdurate facts remain, preventing a compromise solution.

  • Obedient

Definition: doing, or willing to do, what you have been told to do by someone in authority

Example: He always tried his best to be an obedient son.

  • Obese

Definition: extremely fat

Example: Obese people tend to have higher blood pressure than lean people.

  • Objectionable

Definition: unpleasant, offensive, or repugnant

Example: He want people to stop making objectionable content so we’re less tempted to consume it.

  • Objective

Definition: not influenced by personal feelings or beliefs

Example: Analysts produced objective evidence that the world was heading for a global recession.

  • Obligatory

Definition: expected because it usually happens

Example: Several Secret Service agents surrounded the President, all wearing the obligatory raincoat and hat.

  • Obliging

Definition: willing or eager to help

Example: He found an obliging doctor who gave him the drugs he needed.

  • Oblique

Definition: not expressed or done in a direct way

Example: He issued an oblique attack on the President.

  • Oblong

Definition: having a shape that is longer than it is wide

Example: It’s a shrub with narrow, oblong leaves.

  • Obnoxious

Definition: very pleasant or rude

Example: Some of the colleagues say that he’s loud and obnoxious.

  • Obscure

Definition: not clear and difficult to understand or see

Example: His answers were obscure and confusing.

  • Obscene

Definition: offensive, rude, or shocking, usually because of being too obviously related to sex or showing sex

Example: He was jailed for making obscene phone calls.

  • Obsequious

Definition: obedient or attentive to an excessive or servile degree

Example: They were served by obsequious waiters.

  • Observable

Definition: that can be noticed or seen

Example: There’s no observable connection between the two events.

  • Observant

Definition: obeying religious rules or customs

Example: As an observant Muslim, she wore a headscarf.

  • Obsessive

Definition: of the nature of an obsession

Example: I love that obsessive quality.

  • Obsolete

Definition: not in general use any more, having been replaced by something newer and better or more fashionable

Example: We need to replace some obsolete equipment.

  • Obstetric

Definition: relating to the area of medicine that deals with pregnancy and the birth of babies

Example: The hospital needs to be able to offer 24-hour obstetric services.

  • Obstetrical

Definition: of or pertaining to childbirth or obstetrics

Example: On obstetrical examination of the giraffe, a fetal malposition type of dystocia had occurred.

  • Obstinate

Definition: used to describe a problem, situation, or thing that is difficult to deal with, remove, change or defeat

Example: Invading troops met with obstinate resistance by guerilla forces.

  • Obstreperous

Definition: noisy and difficult to control

Example: The boy is cocky and obstreperous.

  • Obstructive

Definition: causing a blockage or obstruction.

Example: All tubing should be cleared of obstructive algae and detritus.

  • Obtuse

Definition: annoyingly insensitive or slow to understand

Example: I like a bit obtuse reporting.

  • Obvious

Definition: easily perceived or understood; clear, self-evident, or apparent.

Example: Unemployment has been the most obvious cost of the recession.

  • Occasional

Definition: not happening or done often or regularly

Example: I play the occasional game of tennis.

  • Occidental

Definition: relating to the western part of the world, especially the countries of Europe and America

Example: The music is a mix of occidental pop and Latin sensuality.

  • Occipital

Definition: relating to the occipital area

Example: A scan of the girl’s brain showed seizure activity in the temporal, parietal, and occipital lobes of the brain.

  • Occlusive

Definition: of or relating to the act of occlusion

Example: Look in the ingredients for occlusive agents that will prevent water loss, such as ceramides and petrolatum.

  • Occult

Definition: relating to magical powers and activities, such as those of witchcraft and astrology

Example: She claims to have occult powers, given to her by some mysterious spirit.

  • Occupational

Definition: relating to or caused by your job

Example: Back problems are an occupational hazard for any desk-bound office worker.

  • Oceanic

Definition: belonging or relating to an ocean or to the sea

Example: Many oceanic islands are volcanic.

  • Ocher

Definition: having a yellowish-orange color

Example: The building has ocher yellow walls and green tiled roofs.

  • Octagonal

Definition: having eight straight sides

Example: There were pictures on every other wall of the octagonal shaped room.

  • Odd

Definition: strange or unexpected

Example: Her father was an odd man.

  • Odious

Definition: extremely unpleasant

Example: Herr Schmidt is certainly the most odious man I have ever met.

  • Odorous

Definition: having an unpleasant smell

Example: The chlorine dioxide neutralizes the odorous sulphur compounds.

  • Odorless

Definition: having no odour

Example: Carbon monoxide is colorless, odorless and tasteless and persists in the air.

  • Offbeat

Definition: not coinciding with the beat

Example: A rapid tempo is essential here, otherwise we will not sense the offbeat hemiolas.

  • Offensive

Definition: used for attacking

Example: Knives of any kind are classed as offensive weapons.

  • Offhand

Definition: not showing or not done with much thought or consideration

Example: His offhand manner disturbed us.

  • Official

Definition: relating to a position of responsibility

Example: He visited China in his official capacity as America’s trade representative.

  • Officious

Definition: assertive of authority in a domineering way, especially with regard to trivial matters

Example: The security people were very officious.

  • Offshore

Definition: situated at sea some distance from the shore

Example: This huge stretch of coastline is dominated by offshore barrier islands.

  • Offside

Definition: on or relating to the side of a vehicle that is furthest from the edge of the road and closest to the centre of the road when you are driving on right side

Example: The offside rear wheels need replacing.

  • Offstage

Definition: (in a theatre) not taking place on the stage and so not visible to the audience

Example: She walked away as the clear winner of both onstage and offstage dancing.

  • Oily

Definition: covered in oil or containing a lot of oil

Example: I have oily skin.

  • Old

Definition: having lived for a long time; no longer young

Example: The old man lay propped up on cushions.

  • Olden

Definition: for a long time ago

Example: There weren’t things like televisions and computers in the olden days.

  • Oldish

Definition: somewhat old

Example: The typewriter, an oldish electric model, stood on the dinning-table.

  • Oldline

Definition: used to describe a business or industry that has existed for a long time

Example: It’s the latest old-line industry to disappear from the region.

  • Oleaginous

Definition: rich in, covered with, or producing oil; oily

Example: Fabrics would quickly become filthy in this oleaginous kingdom.

  • Olfactive

Definition: of or relating to sense of smell

Example: The olfactive descriptions of floral scent from each species was evaluated for a professional perfumer.

  • Olfactory

Definition: concerned with the sense of smell

Example: This olfactory sense develops in the womb.

  • Olympian

Definition: having the qualities of a god

Example: She has maintained an Olympian detachment from the everyday business of the office.

  • Ominous

Definition: suggesting that something unpleasant is likely to happen

Example: There was an ominous silence when I asked whether my contract was going to be renewed.

  • Omnidirectional

Definition: sending or receiving signals in all directions

Example: It also demonstrates a nearly omnidirectional radiation pattern.

  • Omnipotent

Definition: having the power to do anything

Example: The people overthrew the once omnipotent dictator.

  • Omnipresent

Definition: present or having an effect everywhere at the same time

Example: The singer became an omnipresent icon of style and beauty.

  • Omnivorous

Definition: naturally able to eat both plants and meat

Example: Pigs are omnivorous animals.

  • Oncoming

Definition: moving towards you or coming nearer

Example: The car veered onto the wrong side of the road and hit an oncoming truck.

  • Oneiric

Definition: like a dream, or relating to dreams

Example: The film thrills with its indelible, oneiric imagery.

  • Onerous

Definition: causing great difficulty or trouble

Example: The tax bill was aimed at lifting the onerous tax burden from the backs of the middle class.

  • Onetime

Definition: only once

Example: The gym charges a separate, onetime fee to join.

  • Ongoing

Definition: continuing to exist or develop, or happening at the present moment

Example: There are a number of ongoing difficulties with the project.

  • Online

Definition: products, services, or information that can be bought or used on the internet

Example: We’re linked to the online database at our head office.

  • Only

Definition: used to show that there is a single one or very few of something, or that there are no others

Example: I have the only person on the train.

  • Onshore

Definition: on land rather than in the sea

Example: The energy supplier has invested heavily in developing onshore windfarms.

  • Oozy

Definition: of, resembling, or containing mud; slimy

Example: The tank, with its mouldering brickwork, its rusty iron, its dank shrubs and weeds, its oozy canal, had vanished like smoke in the air.

  • Opalescent

Definition: colorless or white like an opal, or changing color like an opal

Example: Elaine turned her opalescent eyes on him.

  • Opaque

Definition: not able to be seen through, not transparent

Example: Bottles were filled with a pale opaque liquid.

  • Open

Definition: allowing access, passage, or a view through an empty space; not closed or blocked

Example: He climbed through the open window.

  • Opencast

Definition: (of mines and mining) excavated from the surface

Example: The mine developed as a series of opencast working, mainly by the use of hydraulic mining methods.

  • Open-mouthed

Definition: having an open mouth, esp. in surprise

Example: There must be many thousands of small businessmen hearing this with open-mouthed astonishment.

  • Operable

Definition: fit, possible, or desirable to use; practicable

Example: Check operable safety features of the car before driving.

  • Operant

Definition: involving changes in behaviour that are caused because good or bad things always happen in connection with the behaviour

Example: As part of the operant conditioning, the cat was rewarded with food when he remained calm during each step of the procedure.

  • Operatic

Definition: extravagantly theatrical; histrionic

Example: She wrung her hands in operatic despair.

  • Operational

Definition: relating to a particular activity

Example: There are operational advantages in putting sales and admin in the same building.

  • Opinionated

Definition: having strong opinions and refuse to accept that they may be strong

Example: Your article is full of some of the most opinionated rubbish I have ever read.

  • Opportune

Definition: happening at a time that is likely to produce success or is convenient

Example: This seems to be an opportune moment for reviving our development plan.

  • Opportunistic

Definition: using a situation to get power or on advantage

Example: He made an opportunistic grab for power, which resulted in a civil war.

  • Opposed

Definition: (of two or more things) contracting or conflicting with each other

Example: The agency is being asked to do two diametrically opposed things.

  • Opposing

Definition: competing or fighting against each other

Example: The article tries to show opposing viewpoints on the issue.

  • Opposite

Definition: situated on the other or further side when seen from a specified or implicit viewpoint; facing

Example: A crowd gathered on the opposite side of the street.

  • Oppressive

Definition: (of weather) close and sultry

Example: The day was sunless and oppressive.

  • Optic

Definition: relating to the eye or vision

Example: Once the optic nerve was severed during the surgery, the surgeon knew the patient would receive the vision without allowing an impulse to the brain.

  • Optical

Definition: relating to light or the ability to see

Example: The glowing cloud was an optical effect.

  • Optimal

Definition: the best or most effective possible in a particular situation

Example: Companies benefit from the optimal use of their resources and personnel.

  • Optimistic

Definition: hoping or believing that good things will happen in the future

Example: She is optimistic about her chances of winning a gold medal.

  • Optimum

Definition: best; most likely to bring success or advantage

Example: A mixture of selected funds is an optimum choice for future security and return on investment.

  • Optional

Definition: available to be chosen but not obligatory

Example: There are several optional tours, for which there will be a small charge.

  • Opulent

Definition: rich in appearance; showing great wealth

Example: He lived an opulent lifestyle that included sports cars and enormous homes.

  • Oracular

Definition: of or relating to an oracle

Example: Apollo had his oracular shrine at Delphi.

  • Oral

Definition: spoken rather than written; verbal

Example: They had reached on oral agreement.

  • Orange

Definition: of a color between red and yellow

Example: The setting sun filled the sky with a deep orange glow.

  • Ordered

Definition: well-organized and has a clear structure

Example: An objective set of rules which we all agree to accept is necessary for any ordered society.

  • Orderly

Definition: well-arranged or organized

Example: She put the letters in three orderly piles.

  • Ordinary

Definition: with no special or distinctive features; normal

Example: He sets out to depict ordinary people.

  • Organic

Definition: not using artificial chemicals in the growing of plants and animals for food and other products

Example: These organic olives are packaged in recycled glass containers.

  • Organizational

Definition: relating to the action of organizing something

Example: She has great organizational skills.

  • Organized

Definition: arranged according to a particular system

Example: The letters had been placed in organized piles, one for each letter of the alphabet.

  • Orgiastic

Definition: wild, uncontrolled behaviour and feeling of great pleasure and excitement

Example: People who put up pagan mistletoe at a Christian ceremony must expect orgiastic behaviour.

  • Oriental

Definition: relating to the countries of East and Southeast Asia

Example: The concrete floor was covered with oriental rugs.

  • Oriented

Definition: used to describe what someone or something is mainly interested in or concerned with

Example: It just show how much she really has a family-oriented mindset.

  • Original

Definition: existing since the beginning, or being the earliest form of something

Example: The gardens have recently been restored to their original glory.

  • Ornamental

Definition: used or grown for ornament

Example: There was a big rectangular poo, not deep, which Thomas Robertson had stocked with ornamental fish.

  • Ornate

Definition: language that tis ornate contains too many complicate words or phrases

Example: Some students are put off studying his work because of the ornate language of the poetry.

  • Ornery

Definition: likely to get angry and argue with people

Example: He had been in an ornery mood all day, arguing with everyone who got in his way.

  • Ornithological

Definition: relating to the study of birds

Example: She works as a sketch artist for an ornithological magazine.

  • Oropharyngeal

Definition: relating to the oropharynx

Example: Sixty patients with oral and oropharyngeal carcinomas were enrolled.

  • Orphaned

Definition: having no parents because they have died

Example: The family took in three orphaned siblings.

  • Orthodox

Definition: (of beliefs, ideas, or activities) considered tradition, normal, and acceptable by most people

Example: We would prefer a more orthodox solution to the problem.

  • Orthogonal

Definition: (of a square matrix) defined so that is product with its transpose results in the identity matrix

Example: An orthogonal matrix, combining the selected levels of attributes, was used to define scenarios.

  • Orthomolecular

Definition: relating to a method of treating chemical imbalances in the body by use of vitamins

Example: She has a private practice in orthomolecular nutrition.

  • Orthoptic

Definition: relating to the treatment or study of problems of the eye muscles, for example having a squint or having double vision

Example: Orthoptic examination and treatment is important in the rehabilitation of low-vision patients.

  • Orthostatic

Definition: relating to standing up straight

Example: If you feel that your blood pressure changes because of the posture and position you are holding, you may be suffering from orthostatic hypotension.

  • Orwellian

Definition: used to describe a political system in which the government tries to control every part of people’s lives, similar to that described in the novel “Nineteen Eighty-Four”, by George Orwell

Example: We don’t want to see a 1984 Orwellian type situation where neighbours are reporting on neighbours.

  • Osseous

Definition: composed of, containing, or resembling bone; bony

Example: Histological diagnosis was reported as osseous cavernous hemangioma.

  • Ossified

Definition: (of habits or ideas) fixed and unable to change

Example: He tried to push liberalizing policies through an ossified bureaucracy.

  • Osteal

Definition: osseous; bony

Example: Presumably, these variations may induce osteal obstruction, preventing mucus drainage and predisposing to chronic rhinosinusitis.

  • Ostensible

Definition: stated or appearing to be true, but not necessarily so

Example: The real dispute which lay behind the ostensible complaint.

  • Ostentatious

Definition: too obviously showing your money, possessions, or power, in an attempt to make other people notice and admire you

Example: They criticized the ostentatious lifestyle of their leaders.

  • Other

Definition: as well as the thing or person already mentioned

Example: The product has many other time-saving features.

  • Otherworldly

Definition: more closely connected to spiritual things than to the ordinary things of life

Example: The children in the picture look delicate and otherworldly, as though they had never run or played.

  • Ototoxic

Definition: causing damage to the ear

Example: The ototoxic effects of radiotherapy have been poorly characterized.

  • Ottoman

Definition: of or relating to the Ottomans or the Ottoman Empire

Example: Under a Ottoman threat of war he obtained in 1826 the convention of empire.

  • Outback

Definition: of such a region

Example: This outback area is a far cry from the city’s concrete jungle.

  • Outboard

Definition: (of an electronic accessory) in a separate container from the device with which it is used

Example: The computer resides in a single cabinet plus some outboard boxes for disk drives.

  • Outbound

Definition: travelling away from a particular point

Example: There has been an increase in outbound traffic leaving Toronto airport for the Caribbean resort.

  • Outdated

Definition: old-fashioned and therefore not as good or as fashionable as something modern

Example: Many hospitals struggle with outdated equipment and facilities.

  • Outdoor

Definition: existing, happening, or done outside, rather than inside a building

Example: The hotel has an outdoor swimming pool.

  • Outer

Definition: at a greater distance from the centre

Example: Ice had formed around the outer edge of the pond.

  • Outermost

Definition: further away

Example: These spacecrafts may send back data about the outermost reaches of the solar system.

  • Outgoing

Definition: (of a person) friendly and energetic and finding it easy and enjoyable to be with others

Example: She has an outgoing personality.

  • Outlandish

Definition: strange and unusual

Example: She liked to dress in outlandish clothes.

  • Outlying

Definition: far away from main towns and cities, or far from the centre of a place

Example: Many of the students travel in by bus from outlying areas.

  • Outmoded

Definition: no longer modern, useful, or necessary

Example: Outmoded working practices are being phased out.

  • Outmost

Definition: most remote; outermost

Example: The outmost islands are rich in various resources but have not been managed yet.

  • Outraged

Definition: feeling outrage

Example: Outraged viewers jumped onto social media to complain about the ending of the series.

  • Outrageous

Definition: unacceptable, offensive, violent, or unusual

Example: He made outrageous claims.

  • Outright

Definition: complete

Example: There was no outright winner in the election.

  • Outside

Definition: coming from another place or organization

Example: The company has called in outside experts.

  • Outsized

Definition: (of profits, payments, etc) extremely large and are considered too large by many people

Example: Companies can’t just ramp up their production capacity and expect to earn outsized profits.

  • Outspoken

Definition: expressing strong opinions very directly without worrying if other people are offended

Example: Mr. Masack is an outspoken critic of the present government.

  • Outspread

Definition: to spread out, extend; expand

Example: Adults have been observed resting with outspread wings on lichen-covered tree-trunks.

  • Outstanding

Definition: clearly very much better than what is usual

Example: It’s an area of outstanding natural beauty.

  • Outstretched

Definition: (especially of a hand or arm) extended or stretched out

Example: She reached across and shook his outstretched hand.

  • Outward

Definition: relating to how people, situations, or things seen to be, rather than how they are inside

Example: The outward appearance of the building has not changed at all in 200 years.

  • Oval

Definition: shaped like a circle that is flattened so that it is like an egg or an ellipse

Example: The plant has oval green leaves marbled with brownish-purple.

  • Ovarian

Definition: of or pertaining to an ovary

Example: Nearly half of women with ovarian cancer see their GP three times before they are diagnosed.

  • Ovate

Definition: shaped like an egg

Example: The cones are very small, ovate and pointed.

  • Overabundant

Definition: too abundant; excessive

Example: We are bombarded with food advertising and an overabundant supply of high fat and high sugar foods.

  • Overactive

Definition: (of part of the body) producing too much of a substance, or reacting too quickly

Example: With an overactive thyroid, metabolism speeds up.

  • Overaged

Definition: over a certain age limit

Example: The college has many overaged students.

  • Overaggressive

Definition: excessively quarrelsome or belligerent

Example: Overaggressive banks poured money they did not have into worldwide expansion.

  • Overall

Definition: in general, rather than in particular, or including all the people or things in a particular group or situation

Example: The overall situation is good, despite a few minor problems.

  • Overambitious

Definition: excessively ambitious

Example: She is let down by her overambitious structure and a lack of sufficient tension.

  • Overanxious

Definition: excessively worried, tense, or uneasy

Example: It’s often fragile, the way she talks, but elegant, with big eyes a window into an overanxious brain.

  • Overarm

Definition: done with the hand or arm passing above the level of the shoulder

Example: The bowler was happy to demonstrate his overarm technique.

  • Overbearing

Definition: too confident and too determined to tell other people what to do, in a that is unpleasant

Example: Milligan had a pompous, overbearing father.

  • Overblown

Definition: stout; obese

Example: Sometimes in the overblown world of modern football, things just need to be said the way they are.

  • Overburdened

Definition: having too much to carry, contain, or deal with

Example: We’re trying to stop development in areas with overburdened roads and schools.

  • Overcareful

Definition: excessively careful

Example: Across the street, she imagined the man with the rockets taking overcareful arm at her.

  • Overcast

Definition: with clouds in the sky and therefore not bright and sunny

Example: The sky was overcast.

  • Overconfident

Definition: having or showing too much confident

Example: Overconfident brashness may not impress an interview panel.

  • Overcritical

Definition: inclined to find fault too readily

Example: The overcritical teacher can discourage originality.

  • Overcrowded

Definition: (of accommodation or a space) filled beyond what is comfortable, safe, or desirable

Example: Infectious diseases can spread in overcrowded prisons.

  • Overdressed

Definition: dressed too elaborately or finely

Example: She was overdressed for the party.

  • Overdue

Definition: not paid on time

Example: The company routinely takes money off wages to collection on overdue debts.

  • Overemotional

Definition: having feeling that are too easily and displayed

Example: We’re not an overemotional family.

  • Overenthusiastic

Definition: excessively enthusiastic

Example: It is a salutary warning to the overenthusiastic reader.

  • Overexcited

Definition: excessively excited

Example: They were forced to hide from overexcited fans who threatened to riot.

  • Overfamiliar

Definition: too well acquainted with

Example: The overfamiliar use of her Christian name was intentional.

  • Overfull

Definition: containing an excessive amount of something

Example: The two singers describe their overfull boat which apparently has a childish look as travelling on a path of hope.

  • Overgenerous

Definition: excessive willing and liberal in giving away one’s time, money, etc

Example: It follows measures to stop grade inflation from overgenerous exam marking.

  • Overgrown

Definition: grown too large or beyond its normal size

Example: The town is only an overgrown village.

  • Overhasty

Definition: excessively hasty

Example: Hard times are showing up overhasty mergers.

  • Overhead

Definition: above your head, usually in the sky

Example: This room needs overhead lighting.

  • Overheated

Definition: having become or been made too hot

Example: Let the overheated engine cool off.

  • Overindulgent

Definition: allowing someone to have more of something enjoyable than is good for them

Example: In part, the researchers pointed to overindulgent adults for raising children to believe they are special no matter what they do.

  • Overladen

Definition: having too heavy a load

Example: It’s a wonder she doesn’t sink into the earth, like an overladen cart on a muddy road.

  • Overland

Definition: (of travel) across the land, and not by sea or air

Example: They’re taking an overland trip across Canada.

  • Overlarge

Definition: excessively large

Example: This tendency is particularly clear in the overlarge section devoted to the 1970s.

  • Overmuch

Definition: (especially in negatives) too much or very much

Example: I don’t have overmuch confidence in Hal.

  • Overnight

Definition: for or during the night

Example: I emptied the closet and put my belongings into the black overnight case.

  • Overoptimistic

Definition: unjustifiable optimistic

Example: These overoptimistic forecasts encourage savers to expect unrealistic bumper returns.

  • Overpowering

Definition: too strong to be able to continue or resist

Example: Fighters were driven back by the overpowering heat of the flames.

  • Overpriced

Definition: too expensive; costing more than it is worth

Example: I went and had an overpriced cup of coffee in the hotel cafeteria.

  • Overprotective

Definition: wishing to protect someone, especially a child, too much

Example: The children of overprotective parents often do not develop the skills they need to take care of themselves when they leave home.

  • Overqualified

Definition: too highly qualified for a particular job

Example: An overqualified person will quickly become dissatisfied.

  • Overrated

Definition: (of something or someone) considered to be better or more important than they really are

Example: In my opinion, she’s a hugely overrated singer.

  • Overseas

Definition: in, from, or connected with another country or countries, especially across the sea

Example: We need to open up overseas markets.

  • Oversensitive

Definition: excessively or unduly sensitive

Example: The problem was traced to an oversensitive protection circuit, a type of circuit breaker.

  • Oversize

Definition: bigger than usual or too big

Example: My daughter loves to wear oversize clothes.

  • Overstuffed

Definition: filled with too much material or too many things

Example: They sat in overstuffed crimson leather chairs.

  • Overt

Definition: done or shown publicly or in an obvious way and not secret

Example: He shows no overt sign of his unhappiness.

  • Overweight

Definition: heavier than is allowed

Example: If your luggage is overweight, you have to pay extra.

  • Overwhelming

Definition: very great in amount

Example: His party won overwhelming support.

  • Ovoid

Definition: having the same shape as an egg, or of a similar shape

Example: The ovoid seed pods burst when ripe.

  • Owlish

Definition: (of glasses) resembling the large round eyes of an owl

Example: Her owlish glasses made her look studious.

  • Own

Definition: belonging to or done by a particular person or thing

Example: They can’t handle their own children.

  • Ownerless

Definition: having no owner

Example: Their ownerless property is destroyed.

  • Oxidizable

Definition: able to be oxidized

Example: Organic oxidized carbon was also observed in the forest soils.

Positive Adjectives That Start with O to Describe a Person

Without adjectives, we won’t be able to express how a person is like. Below are some adjectives that start with O to describe a person to help you out in such case in daily life.

1. Obedient

Definition: complying or willing to comply with an order or request; submissive to another’s authority

Synonyms: compliant, tractable, amenable

Example: He was always obedient to his father’s wishes.

2. Obliging

Definition: ready to do favors; helpful; courteous; accommodating

Synonyms: helpful, accommodating, willing

Example: He found an obliging doctor who gave him the drugs he needed.

3. Observant

Definition: paying careful attention; keenly watchful; perceptive or alert

Synonyms: alert, sharp-eyed, eagle-eyed

Example: An observant shop assistant had remembered exactly what the man was wearing.

4. Omnipotent

Definition: having unlimited power or authority; all-powerful

Synonyms: supreme, almighty, dictatorial

Example: Nature is powerful, but not omnipotent: history too often influences events.

5. Omniscient

Definition: knowing everything, all-seeing

Synonyms: all-knowing, all-wise

Example: In other words, only an omniscient analyst can judge the degrees of cost and pay-off to both utterer and receiver.

6. Optimistic

Definition: having the tendency to take the most hopeful or cheerful view of matters or to expect the best outcome

Synonyms: cheerful, positive, hopeful

Example: I’m very optimistic about our chances of success.

7. Opulent

Definition: very wealthy or rich; characterized by abundance; luxuriant

Synonyms: luxurious, sumptuous, palatial

Example: Most of the cash went on supporting his opulent lifestyle.

8. Open-minded

Definition: willing to consider new ideas; unprejudiced

Synonyms: unbiased, unprejudiced, accepting

Example: Try to keep an open mind until you’ve heard all the facts.

Positive Adjectives That Start with O to Describe an Event

Some adjectives require a certain context to be uttered. For example, below descriptive words that start with O can be used when describing an event.

1. Occasional

Definition: of irregular occurrence; happening now and then; infrequent

Synonyms: intermittent, irregular, infrequent

Example: The weather was good except for an occasional shower.

2. Opaque

Definition: not letting light pass through; not transparent or translucent; not reflecting light; not shining or lustrous;

Synonyms: dull, dark, cloudy, blurred

Example: You can always use opaque glass if you need to block a street view.

3. Opportune

Definition: happening or done at the right time; seasonable; well-timed; timely

Synonyms: suspicious, propitious, favorable

Example: This would seem to be an opportune moment for reviving our development plan.

4. Original

Definition: having to do with an origin, first, earliest; fresh, new, novel; capable of or given to inventing or creating something new, or thinking or acting in an individual, fresh way; coming from someone as the originator, maker, author, etc

Synonyms: indigenous, native, first, early

Example: Never be afraid to be yourself. Remember, an original is worth more than a copy.

5. Orthodox

Definition: conforming to the usual beliefs or established doctrines, as in religion, politics, etc.; approved or conventional

Synonyms: conservative, traditional, devout

Example: We would prefer a more orthodox approach/solution to the problem.

6. Ostentatious

Definition: characterized by or given to pretentious or conspicuous show in an attempt to impress others

Synonyms: showy, conspicuous, obtrusive

Example: They criticized the ostentatious lifestyle of their leaders.

7. Obtainable

Definition: capable of being acquired

Synonyms: available, in circulation, in season

Example: Buff Fitness Center assured obtainable results for every client simply by sticking to a daily 45-minute exercise.

8. Ongoing

Definition: something that is still going on at the present time and is going to continue

Synonyms: underway, in progress, happening

Example: Training is part of our ongoing career development program.

9. Operative

Definition: functioning or having effect

Synonyms: in force, effective, valid

Example: The commercial telephone service was no longer operative.

10. Obligatory

Definition: required by a legal, moral, or other rule; compulsory

Synonyms: compulsory, mandatory, incumbent

Example: The college authorities have now made these classes obligatory.

11. Occupational

Definition: relating to a job or profession

Synonyms: professional, vocational, business

Example: For many years, experts in occupational health have puzzled over symptoms reported by office workers, including headache, nausea and fatigue.

12. One-time

Definition: Belonging to some prior time

Synonyms: sometime, erstwhile, as was

Example: The scholarship is available on a competitive basis and is a onetime award.

Positive Adjectives That Start with O to Describe a Place

The more adjectives you learn, the more freedom you’ll get when trying to express yourself in everyday life. So keep on learning the following adjectives that start with the letter O.

1. Opulent

Definition: ostentatiously, costly and luxurious.

Synonyms: luxurious, sumptuous, lavish

Example: These were the glittering and opulent reminders of the medieval city.

2. Outstanding

Definition: prominent; distinguished; excellent; marked by superiority or distinction

Synonyms: excellent, marvelous, magnificent

Example: This is an area of outstanding natural beauty.

3. Open

Definition: someone or something which is not closed

Synonyms: unlocked, unfolded, unlatched

Example: He could see a green open space just beyond; and then the woods seemed to be thicker and darker.

4. Ornamental

Definition: serving or intended as an ornament; decorative.

Synonyms: fancy, attractive, artistic

Example: The stream was dammed up to form ornamental lakes.

5. Ornate

Definition: elaborately or highly decorated

Synonyms: decorated, embellished, adorned

Example: The church has an ornate black and white marbled interior.

6. Oaken

Definition: Consisting of or made of wood of the oak tree

Synonyms: oak tree, oak wart, woody

Example: A new oaken enclosure was built and new wiring and electric bellows bought.

7. Odorless

Definition: having no odor, fragrance-free

Synonyms: unscented, deodorized, un-perfumed

Example: the chemical compound is not toxic as such and it is odorless.

8. Official

Definition: Given official status as a national or state institution

Synonyms: formal, ceremonial, pompous

Example: The mayor presented him with a gold medal at an official city reception.

9. Offshore

Definition: At some distance from the shore

Synonyms: away from the shore line, shoreward

Example: His money is in an offshore island bank.

Positive Adjectives That Start with O to Describe Emotions, Personality, and Feelings

Without adjectives, it is basically impossible to express our feelings. Are you “glad”, “sad”, “angry”, “excited”? These are all common adjectives used in day-to-day life. And below are more adjectives with letter O for similar use.

1. Objectionable

Definition: disagreeable; offensive

Synonyms: distasteful, unpleasant, displeasing

Example: His drunken behavior was extremely objectionable.

2. Overjoyed

Definition: extremely happy

Synonyms: ecstatic, euphoric, delighted

Example: He was overjoyed to see his mother again.

3. Obliging

Definition: Showing a cheerful willingness to do favors for others

Synonyms: helpful, accommodating, willing

Example: He is an extremely pleasant and obliging man.

4. Obvious

Definition: easily perceived or understood; clear, self-evident, or apparent

Synonyms: evident, clear, conspicuous

Example: Lack of qualifications is an obvious disadvantage.

Negative Adjectives That Start with O to Describe a Person

If you can’t find a proper word to describe the person you hate, the following adjective words that start with O to describe a person may help.

1. Odd

Definition: different to what is usual or expected; strange

Synonyms: strange, peculiar, weird

Example: As a manager, it is so hard to deal with odd workers.

2. Obese

Definition: very fat; stout; corpulent

Synonyms: overweight, gross, stout

Example: Obese people tend to have higher blood pressure than lean people.

3. Obtuse

Definition: slow to understand or perceive; dull or insensitive

Synonyms: stupid, dull, unintelligent

Example: He wondered if the doctor was being deliberately obtuse.

4. Offensive

Definition: unpleasant, as to the senses; disgusting; repugnant; causing resentment, anger, etc

Synonyms: insulting, rude, derogatory

Example: His comments were deeply offensive to a large number of single mothers.

5. Oafish

Definition: Ill-mannered and coarse, contemptible in behavior or appearance

Synonyms: stupid, foolish, idiotic

Example: My fellow, oafish roommate has shared my computer with me periodically.

6. Oblivious

Definition: not aware of or concerned about what is happening around one

Synonyms: unaware, heedless, insensible

Example: He seemed oblivious to the fact that he had hurt her.

7. Obstinate

Definition: Resistant to guidance or discipline

Synonyms: stubborn, unyielding, inflexible

Example: The most obstinate farmers were persecuted and imprisoned.

8. Obstructive

Definition: causing or tending to cause deliberate difficulties and delays

Synonyms: uncooperative, awkward, disobliging

Example: Mr Smith was obstructive and refused to follow correct procedure.

9. Old

Definition: having lived for a long time; no longer young

Synonyms: elderly, mature, aged

Example: There is no better looking-glass than an old friend

10. Oversized

Definition: bigger than the usual size

Synonyms: bulging, floppy, droopy

Example: Fashion gurus dictate crazy ideas such as squeezing oversized bodies into tight trousers.

11. Oily

Definition: containing oil

Synonyms: greasy, fatty, buttery

Example: When she was younger, she had very oily skin.

Negative Adjectives That Start with O to Describe an Event

If you are a non-English speaking and hope to sound more native, try to include following describing words beginning with O in you daily talks.

1. Obscure

Definition: not discovered or known about; uncertain

Synonyms: uncertain, doubtful, unclear

Example: The origins of the tradition have become obscure.

2. Obsolete

Definition: no longer in use or practice; discarded

Synonyms: outdated, old-fashioned, outmoded

Example: Electronic banking may make over the counter transactions obsolete.

3.  Opposing

Definition: set against; placed opposite, in balance or contrast; contending with in speech or action

Synonyms: rival, opposite, combatant

Example: The soldiers battled against the opposing army all day.

4. Obscene

Definition: offensive to morality or decency; indecent; depraved

Synonyms: indecent, salacious, smutty, pornographic

Example: In the raid, police found several boxes of obscene videotapes.

5. Opposite

Definition: different in every way; exactly contrary

Synonyms: conflicting, incompatible, contrasting

Example: They hit a truck coming in the opposite direction.

6. Offline

Definition: not controlled by or directly connected to a computer or the internet.

Synonyms: disconnected, logged off, connectionless

Example: If one or more modules are offline, you will need to repeat this call when all modules are available online.

Negative Adjectives That Start with O to Describe a Place

Adjectives are what make a sentence colorful and appealing. But you have to use choose the correct ones and use them correctly. Check below adjectives that start with O together with definitions, synonyms and examples to help you better understand them.

1. Odorous

Definition: having or giving off an odor

Synonyms: smelly, stinking, reeking

Example: This can in fact be quite useful in some circumstances such as where a person works in an odorous environment.

2. obdurate

Definition: Showing unfeeling resistance to tender feelings

Synonyms: stubborn, obstinate, intransigent

Example: Actually, there are some fairly obdurate myths about the London climate.

3. Occupied

Definition: (of a building, seat, etc.) being used by someone

Synonyms: inhabited, tenanted, live in

Example: Only the ground floor is fully occupied.

4. Odoriferous

Definition: having or giving off a smell, especially an unpleasant one

Synonyms: aromatic, pungent, savory

Example: These odoriferous organic compounds contain numerous ingredients generally classified into four main groups which are characteristic of the majority of essential oils.

Negative Adjectives That Start with O to Describe Emotions, Personality, and Feelings

List of adjectives that start with O is kind of small in comparison to other more common letters, which means less time and efforts needed to master them all.

1. Ominous

Definition: giving the worrying impression that something bad is going to happen; threateningly inauspicious

Synonyms: menacing, baleful, sinister

Example: There was an ominous silence at the other end of the phone.

2.Outrageous

Definition: having the nature of, involving, or doing great injury or wrong; exceeding all bounds of decency or reasonableness; very offensive or shocking; unrestrained

Synonyms: shocking, disgraceful, appalling

Example: I must make apologies for my outrageous behavior.

3. Obnoxious

Definition: extremely unpleasant, causing disapproval

Synonyms: nasty, distasteful, disagreeable

Example: I have been in restaurants where the human customers have been loud, rude and obnoxious.

4. Oppressive

Definition: inflicting harsh and authoritarian treatment

Synonyms: harsh, cruel, brutal

Example: The oppressive afternoon heat had quite tired him out.

Final Thoughts on Adjectives That Start with O

Do you like these adjectives that start with the letter O we sorted out for you? We hope you find them helpful.

Generally, nouns are one of the most important parts of speech. But adjectives make your speech more accurate and understandable. The thing with adjectives is you never want to overdo them.

Too many adjectives can bulk up a sentence, reducing its fluidity. So remember, only to use these adjectives that start with O where appropriate.

Ps. See also positive words that start with O, nouns that start with O and verbs that start with O.

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