Adjectives That Start with O | List, Exercise & Examples

List of Positive Adjectives That Start With O

Adjective	Definition	Example Sentence
Obliging	Willing to help or do favors.	The obliging waiter quickly fulfilled our requests.
Observant	Quick to notice details.	She’s very observant, noticing even minor changes.
Odds-on	Having a strong likelihood of success.	It’s an odds-on favorite to win the competition.
Okay (OK)	Satisfactory or acceptable.	The food was okay, but not exceptional.
Omnicompetent	Capable of handling any situation.	The omnicompetent manager resolved all issues efficiently.
One-of-a-kind	Unique and unparalleled.	Her one-of-a-kind creativity set her apart from others.
Opalescent	Showing a play of colors like that of an opal.	The sky had an opalescent glow at sunset.
Open-hearted	Generous and kind.	He welcomed us with an open-hearted smile.
Open-minded	Receptive to new ideas or experiences.	She is very open-minded about different cultures.
Opportune	Happening at the right time.	His arrival was opportune, just when we needed help.
Optimal	Best or most favorable.	The room temperature was kept at an optimal level for comfort.
Optimistic	Hopeful and confident about the future.	She remained optimistic despite the challenges.
Optimum	The most favorable or advantageous.	The athlete was in optimum condition for the race.
Opulent	Luxurious and lavish.	They lived in an opulent penthouse overlooking the city.
Orderly	Neat and organized.	The files were arranged in an orderly manner.
Originative	Highly creative and innovative.	His originative ideas revolutionized the industry.
Ornate	Elaborately decorated.	The palace was filled with ornate furnishings.
Orotund	Full, strong, and imposing in sound.	His orotund voice captured everyone’s attention.
Outgoing	Friendly and socially confident.	Her outgoing personality made her popular among peers.
Out-of-this-world	Extremely impressive or amazing.	The dessert was out-of-this-world delicious.
Outstanding	Exceptionally good.	She received an award for her outstanding performance.
Overjoyed	Extremely happy or elated.	He was overjoyed to hear the good news.

List of Negative Adjectives That Start With O

Adjective	Definition	Example Sentence
Objectionable	Unpleasant or offensive.	His objectionable comments made everyone uncomfortable.
Oblique	Not direct or clear.	She gave an oblique answer to avoid the question.
Obliterated	Completely destroyed or wiped out.	The village was obliterated by the hurricane.
Oblivious	Unaware or inattentive.	He was oblivious to the warning signs.
Obnoxious	Extremely unpleasant or annoying.	His obnoxious behavior ruined the party.
Obscene	Offensive or indecent.	The movie was banned due to its obscene content.
Obscure	Not well-known or difficult to understand.	The book was full of obscure references.
Obstinate	Stubborn and unwilling to change.	She remained obstinate despite the evidence.
Obstructive	Causing or tending to cause a blockage.	His obstructive attitude delayed the project.
Obtrusive	Noticeable in an unpleasant way.	The bright neon sign was obtrusive in the quaint town.
Obtuse	Slow to understand or insensitive.	He was too obtuse to grasp the meaning of her words.
Odious	Extremely unpleasant or repulsive.	The dictator was known for his odious deeds.
Offensive	Causing someone to feel upset or insulted.	His remarks were deeply offensive.
Officious	Overly eager to offer unwanted help or advice.	The officious clerk kept interrupting us.
Ominous	Suggesting something bad is about to happen.	The dark clouds looked ominous before the storm.
Onerous	Burdensome or difficult to endure.	The onerous task left him exhausted.
Opinionated	Holding strong, inflexible opinions.	Her opinionated arguments left no room for discussion.
Opportunistic	Exploiting situations for personal gain.	His opportunistic behavior earned him distrust.
Oppressive	Unjustly harsh or tyrannical.	The oppressive heat made it hard to focus.
Ostentatious	Showy and intended to impress.	Her ostentatious jewelry drew unwanted attention.
Overbearing	Domineering and bossy.	His overbearing personality stifled creativity.
Overblown	Exaggerated and overdone.	The speech was full of overblown rhetoric.
Overloaded	Burdened with too much.	The overloaded server crashed frequently.
Oversimplified	Simplified to the point of misrepresentation.	The problem was oversimplified in the report.

Illustration of Adjectives That Start with O

List of Neutral Adjectives That Start With O

Adjective	Definition	Example Sentence
Obese	Extremely overweight.	The doctor advised the obese patient to adopt a healthier lifestyle.
Obsolete	No longer in use or outdated.	The typewriter has become obsolete with the advent of computers.
Obvious	Easily perceived or understood.	It was obvious that she was upset.
Occasional	Happening now and then.	He enjoys an occasional trip to the beach.
Odd	Unusual or strange.	The house had an odd shape compared to others.
Offbeat	Unconventional or quirky.	Her offbeat sense of humor made her stand out.
Oily	Covered with or containing oil.	His hands were oily after working on the car.
Older	Having lived for a longer time.	She’s much older than her younger siblings.
Old-fashioned	Outdated or not modern.	He prefers wearing old-fashioned clothes.
Omnipotent	Having unlimited power or authority.	In mythology, Zeus was considered omnipotent.
Omniscient	Knowing everything.	The narrator in the novel seemed almost omniscient.
Omnivorous	Eating both plants and animals.	Bears are omnivorous, consuming a variety of foods.
Opaque	Not transparent or clear.	The glass was opaque, blocking the sunlight.
Operable	Capable of being used or operated.	The machine was still operable despite minor damage.
Operative	Functioning or having an effect.	The operative word in her statement was “immediately.”
Opposing/Opposed	In conflict or contrast.	They had opposing viewpoints on the issue.
Opposable	Able to be placed against something, often referring to thumbs.	Humans have opposable thumbs.
Opposite	Completely different or contrary.	They have opposite tastes in music.
Optional	Not required but available as a choice.	Attendance at the workshop is optional.
Oral	Relating to the mouth or spoken.	The exam includes both written and oral components.
Orange	A color between red and yellow.	She wore a bright orange dress.
Ordinary	Commonplace or unremarkable.	He led an ordinary life in a small town.
Original	Not derived from something else; unique.	Her idea was truly original and innovative.
Ornamental	Serving as decoration.	The vase was purely ornamental and not functional.
Orthodox	Conforming to traditional beliefs or practices.	He follows an orthodox approach to medicine.
Outlandish	Bizarre or extremely unusual.	His outlandish outfit caught everyone’s attention.

List of O Adjectives To Describe a Person

Adjective	Definition	Example Sentence
Oafish	Clumsy or lacking social grace.	His oafish behavior embarrassed his friends at the party.
Obedient	Willing to follow orders or comply with rules.	The obedient child quickly tidied up her room.
Obeisant	Showing respect or submission.	The knights gave an obeisant bow to their king.
Obsessive	Excessively focused on a particular thing.	He’s obsessive about keeping his desk organized.
Occupied	Busy or actively engaged in something.	She’s too occupied with work to join the event.
Ornery	Easily annoyed or difficult to deal with.	The ornery neighbor complained about every little thing.
Outcast	Rejected by society or a group.	He felt like an outcast after being excluded from the team.
Outdoorsy	Fond of outdoor activities.	She’s an outdoorsy person who loves hiking and camping.
Outrageous	Shockingly bad or excessive.	His outrageous remarks left everyone speechless.
Outspoken	Open and frank in expressing opinions.	She’s very outspoken about her political views.
Overachieving	Achieving more than expected or required.	The overachieving student excelled in every subject.
Overbold	Excessively daring or confident.	His overbold actions got him into trouble.
Overconfident	Too sure of oneself, often leading to mistakes.	The overconfident rookie underestimated his opponent.
Overcritical	Excessively judgmental or fault-finding.	She tends to be overcritical of her own work.
Overextended	Taking on too many responsibilities or tasks.	The overextended manager struggled to meet deadlines.
Overprotective	Excessively concerned about someone's safety.	His overprotective parents rarely let him go out alone.
Overqualified	Having qualifications that exceed what is needed.	She was overqualified for the entry-level job.
Overwrought	Extremely agitated or overly emotional.	He was overwrought with worry after the accident.

Featured Adjectives Grouped by Topics

1. Personality Traits

Positive: Observant, Optimistic, Open-minded.
Negative: Obnoxious, Overbearing, Opinionated.

2. Describing Appearance

Oblique, Opulent, Ordinary.

3. Emotional States

Optimistic, Oblivious, Ominous.

Common Mistakes

Confusing "objective" and "obligatory"

Mistake: "His opinion is obligatory."
Correction: "His opinion is objective."

Overusing "outstanding"

Tip: Reserve "outstanding" for truly exceptional cases to maintain its impact.

FAQ

What is the difference between "observant" and "oblivious"?

"Observant" means being quick to notice details, while "oblivious" means being unaware or inattentive.

Is "objective" always a positive trait?

Generally, yes. Being objective is seen as fair and impartial, especially in decision-making.

Can "opulent" describe a person?

Typically, "opulent" describes luxurious objects or settings, but it can describe a person’s style or lifestyle.

How can "ominous" be used effectively?

"Ominous" suggests a forewarning of something bad, e.g., "The ominous clouds signaled an approaching storm."

Is "ordinary" a neutral or negative adjective?

"Ordinary" is neutral but can imply something is unremarkable in certain contexts.