Words That Start With O: Enhance Your Vocabulary Easily

Discover a variety of interesting words that start with the letter ‘O’ and expand your vocabulary.

1. Oasis: A fertile spot in a desert where water is found.
2. Oatmeal: A porridge made from oats.
3. Obedient: Complying or willing to comply with orders or requests.
4. Obese: Overweight, having excessive body fat.
5. Objective: Not influenced by personal feelings or opinions in considering and representing facts.
6. Obligate: To bind legally or morally.
7. Oblique: Neither parallel nor at a right angle to a specified or implied line; slanting.
8. Obliterate: To destroy utterly; wipe out.
9. Obnoxious: Extremely unpleasant.
10. Obscure: Not discovered or known about; uncertain.
11. Observe: To notice or perceive (something) and register it as being significant.
12. Obsolete: No longer produced or used; out of date.
13. Obstacle: A thing that blocks one’s way or prevents or hinders progress.
14. Obstinate: Stubbornly refusing to change one’s opinion or chosen course of action.
15. Obstruct: To block or impede.
16. Obtain: To get, acquire, or secure something.
17. Obvious: Easily perceived or understood; clear, self-evident.
18. Occasion: A particular time or instance of an event.
19. Occupy: To fill or take up space or time.
20. Occur: To happen or take place.
21. Ocean: A very large expanse of sea.
22. Octagon: A plane figure with eight straight sides and angles.
23. October: The tenth month of the year.
24. Ocular: Of or connected with the eyes or vision.
25. Odor: A distinctive smell, especially an unpleasant one.
26. Offend: Cause to feel upset, annoyed, or resentful.
27. Offer: Present or proffer (something) for acceptance or rejection.
28. Office: A room, set of rooms, or building used for commercial, professional, or bureaucratic work.
29. Officer: A person holding a position of command or authority in the armed services, a public department, or a commercial firm.
30. Official: Relating to an authority or public body and its duties, actions, and responsibilities.
31. Ogle: Stare at in a lecherous manner.
32. Omission: A person or thing omitted or neglected.
33. Omnivore: An animal or person that eats food of both plant and animal origin.
34. Onerous: Involving an amount of effort and difficulty that is oppressively burdensome.
35. Opaque: Not able to be seen through; not transparent.
36. Opera: A dramatic work in one or more acts, set to music for singers and instrumentalists.
37. Operate: Control the functioning of; use and manage (a machine, process, or system).
38. Opinion: A view or judgment formed about something, not necessarily based on fact or knowledge.
39. Opponent: Someone who competes against or fights another in a contest, game, or argument.
40. Opportunity: A set of circumstances that makes it possible to do something.
41. Oppress: Keep (someone) in subservience and hardship.
42. Optimal: Best or most favorable; optimum.
43. Optimist: A person who tends to be hopeful and confident about the future or the success of something.
44. Option: A thing that is or may be chosen.
45. Oral: Spoken rather than written; of the mouth.
46. Orange: A citrus fruit and its color.
47. Orbit: The curved path of a celestial object or spacecraft around a star, planet, or moon.
48. Orchard: A piece of enclosed land planted with fruit trees.
49. Ordain: Order or decree (something) officially.
50. Ordeal: A painful or horrific experience.
51. Order: The arrangement or disposition of people or things in relation to each other.
52. Ordinary: With no special or distinctive features; normal.
53. Organic: Relating to or derived from living matter.
54. Organize: Arrange into a structured whole; order.
55. Orient: Align or position (something) relative to the points of a compass or other specified positions.
56. Origami: The Japanese art of folding paper into decorative shapes and figures.
57. Origin: The point or place where something begins, arises, or is derived.
58. Original: Present or existing from the beginning; first or earliest.
59. Ornate: Made in an intricate shape or decorated with complex patterns.
60. Oscillate: Move or swing back and forth in a regular rhythm.
61. Ostracize: Exclude from a society or group.
62. Ostentatious: Characterized by vulgar or pretentious display; designed to impress or attract notice.
63. Other: Used to refer to a person or thing that is different or distinct from one already mentioned or known about.
64. Ought: Used to indicate duty or correctness, typically when criticizing someone’s actions.
65. Ounce: A unit of weight of one sixteenth of a pound avoirdupois (approximately 28 grams).
66. Outbreak: The sudden or violent start of something unwelcome, such as war, disease, etc.
67. Outcome: The way a thing turns out; a consequence.
68. Outdoors: In or into the open air; outside a building or shelter.
69. Outer: Situated on or toward the outside.
70. Outfit: A set of clothes worn together, typically for a particular occasion or purpose.
71. Outgoing: Friendly and socially confident.
72. Outlet: A means by which something is expressed, achieved, or released.
73. Outline: A line or set of lines enclosing or indicating the shape of an object in a sketch or diagram.
74. Output: The amount of something produced by a person, machine, or industry.
75. Outrage: An extremely strong reaction of anger, shock, or indignation.
76. Outstanding: Exceptionally good.
77. Oval: Having a rounded and slightly elongated outline or shape, like that of an egg.
78. Oven: An enclosed compartment, usually part of a stove, for cooking and heating food.
79. Overcome: Succeed in dealing with (a problem or difficulty).
80. Overhead: Situated above the level of the head.
81. Overlap: Extend over so as to cover partly.
82. Overlook: Fail to notice something.
83. Overseas: In or to a foreign country, especially one across the sea.
84. Oversight: An unintentional failure to notice or do something.
85. Overt: Done or shown openly; plainly apparent.
86. Overture: An orchestral piece at the beginning of a musical composition.
87. Owe: Have an obligation to pay or repay (something, especially money) in return for something received.
88. Owl: A nocturnal bird of prey with large eyes and a flat face.
89. Owner: A person who owns something.
90. Oxide: A binary compound of oxygen with another element or group.
91. Oxygen: A chemical element with symbol O and atomic number 8, necessary for most forms of life on Earth.
92. Oyster: A marine mollusk that has a rough irregular shell, often cultivated for its edible muscle and pearls.
93. Ozone: A reactive form of oxygen that is a bluish gas at room temperature, has a characteristic pungent odor, and is a powerful oxidant that deteriorates rubber and other materials.
94. Opaque: Not able to be seen through; not transparent.
95. Operetta: A short opera, usually on a light or humorous theme and typically having spoken dialogue.
96. Ophthalmologist: A specialist in the branch of medicine concerned with the study and treatment of disorders and diseases of the eye.
97. Optician: A person qualified to make and supply eyeglasses and contact lenses for the correction of vision.
98. Ornithologist: A person who studies or is an expert on birds.
99. Orthodox: Adhering to what is traditionally accepted as right or true; established and approved.
100. Outsource: Obtain (goods or a service) from an outside or foreign supplier, especially in place of an internal source.