- oaken adj. Made of or from oak.
- oakum n. Hemp-fiber obtained by untwisting and picking out
loosely the yarns of old hemp rope.
- obdurate adj. Impassive to feelings of humanity or pity.
- obelisk n. A square shaft with pyramidal top, usually
monumental or commemorative.
- obese adj. Exceedingly fat.
- obesity n. Excessive fatness.
- obituary adj. A published notice of a death.
- objective adj. Grasping and representing facts as they
are.
- objector n. One who objects, as to a proposition, measure, or
ruling.
- obligate v. To hold to the fulfillment of duty.
- obligatory adj. Binding in law or conscience.
- oblique adj. Slanting; said of lines.
- obliterate v. To cause to disappear.
- oblivion n. The state of having passed out of the memory or of
being utterly forgotten.
- oblong adj. Longer than broad: applied most commonly to
rectangular objects considerably elongated
- obnoxious adj. Detestable.
- obsequies n. Funeral rites.
- obsequious adj. Showing a servile readiness to fall in with
the wishes or will of another.
- observance n. A traditional form or customary act.
- observant adj. Quick to notice.
- observatory n. A building designed for systematic astronomical
observations.
- obsolescence n. The condition or process of gradually falling
into disuse.
- obsolescent adj. Passing out of use, as a word.
- obsolete adj. No longer practiced or accepted.
- obstetrician n. A practitioner of midwifery.
- obstetrics n. The branch of medical science concerned with the
treatment and care of women during pregnancy.
- obstinacy n. Stubborn adherence to opinion, arising from
conceit or the desire to have one's own way.
- obstreperous adj. Boisterous.
- obstruct v. To fill with impediments so as to prevent passage,
either wholly or in part.
- obstruction n. Hindrance.
- obtrude v. To be pushed or to push oneself into undue
prominence.
- obtrusive adj. Tending to be pushed or to push oneself into
undue prominence.
- obvert v. To turn the front or principal side of (a thing)
toward any person or object.
- obviate v. To clear away or provide for, as an objection or
difficulty.
- occasion n. An important event or celebration.
- Occident n. The countries lying west of Asia and the Turkish
dominions.
- occlude v. To absorb, as a gas by a metal.
- occult adj. Existing but not immediately perceptible.
- occupant n. A tenant in possession of property, as
distinguished from the actual owner.
- occurrence n. A happening.
- octagon n. A figure with eight sides and eight angles.
- octave n. A note at this interval above or below any other,
considered in relation to that other.
- octavo n. A book, or collection of paper in which the sheets
are so folded as to make eight leaves.
- octogenarian adj. A person of between eighty and ninety
years.
- ocular adj. Of or pertaining to the eye.
- oculist n. One versed or skilled in treating diseases of the
eye.
- oddity n. An eccentricity.
- ode n. The form of lyric poetry anciently intended to be
sung.
- odious adj. Hateful.
- odium n. A feeling of extreme repugnance, or of dislike and
disgust.
- odoriferous adj. Having or diffusing an odor or scent,
especially an agreeable one.
- odorous adj. Having an odor, especially a fragrant one.
- off adj. Farther or more distant.
- offhand adv. Without preparation.
- officiate v. To act as an officer or leader.
- officious adj. Intermeddling with what is not one's
concern.
- offshoot n. Something that branches off from the parent
stock.
- ogre n. A demon or monster that was supposed to devour human
beings.
- ointment n. A fatty preparation with a butter-like consistency
in which a medicinal substance exists.
- olfactory adj. of or pertaining to the sense of smell.
- olive-branch n. A branch of the olive-tree, as an emblem of
peace.
- ominous adj. Portentous.
- omission n. Exclusion.
- omnipotence n. Unlimited and universal power.
- Omnipotent adj. Possessed of unlimited and universal
power.
- omniscience n. Unlimited or infinite knowledge.
- omniscient adj. Characterized by unlimited or infinite
knowledge.
- omnivorous adj. Eating or living upon food of all kinds
indiscriminately.
- onerous adj. Burdensome or oppressive.
- onrush n. Onset.
- onset n. An assault, especially of troops, upon an enemy or
fortification.
- onslaught n. A violent onset.
- onus n. A burden or responsibility.
- opalescence n. The property of combined refraction and
reflection of light, resulting in smoky tints.
- opaque adj. Impervious to light.
- operate v. To put in action and supervise the working of.
- operative adj. Active.
- operator n. One who works with or controls some machine or
scientific apparatus.
- operetta n. A humorous play in dialogue and music, of more
than one act.
- opinion n. A conclusion or judgment held with confidence, but
falling short of positive knowledge.
- opponent n. One who supports the opposite side in a debate,
discussion, struggle, or sport.
- opportune adj. Especially fit as occurring, said, or done at
the right moment.
- opportunist n. One who takes advantage of circumstances to
gain his ends.
- opportunity n. Favorable or advantageous chance or
opening.
- opposite adj. Radically different or contrary in action or
movement.
- opprobrium n. The state of being scornfully reproached or
accused of evil.
- optic n. Pertaining to the eye or vision.
- optician n. One who makes or deals in optical instruments or
eye-glasses.
- optics n. The science that treats of light and vision, and all
that is connected with sight.
- optimism n. The view that everything in nature and the history
of mankind is ordered for the best.
- option n. The right, power, or liberty of choosing.
- optometry n. Measurement of the powers of vision.
- opulence n. Affluence.
- opulent adj. Wealthy.
- oral adj. Uttered through the mouth.
- orate v. To deliver an elaborate or formal public speech.
- oration n. An elaborate or formal public speech.
- orator n. One who delivers an elaborate or formal speech.
- oratorio n. A composition for solo voices, chorus, and
orchestra, generally taken from the Scriptures.
- oratory n. The art of public speaking.
- ordeal n. Anything that severely tests courage, strength,
patience, conscience, etc.
- ordinal n. That form of the numeral that shows the order of
anything in a series, as first, second, third.
- ordination n. A consecration to the ministry.
- ordnance n. A general name for all kinds of weapons and their
appliances used in war.
- orgies n. Wild or wanton revelry.
- origin n. The beginning of that which becomes or is made to
be.
- original adj. Not copied nor produced by imitation.
- originate v. To cause or constitute the beginning or first
stage of the existence of.
- ornate adj. Ornamented to a marked degree.
- orthodox adj. Holding the commonly accepted faith.
- orthodoxy n. Acceptance of the common faith.
- orthogonal adj. Having or determined by right angles.
- orthopedic adj. Relating to the correcting or preventing of
deformity
- orthopedist n. One who practices the correcting or preventing
of deformity
- oscillate v. To swing back and forth.
- osculate v. To kiss.
- ossify v. to convert into bone.
- ostentation n. A display dictated by vanity and intended to
invite applause or flattery.
- ostracism n. Exclusion from intercourse or favor, as in
society or politics.
- ostracize v. To exclude from public or private favor.
- ought v. To be under moral obligation to be or do.
- oust v. To eject.
- out-and-out adv. Genuinely.
- outbreak n. A sudden and violent breaking forth, as of
something that has been pent up or restrained.
- outburst n. A violent issue, especially of passion in an
individual.
- outcast n. One rejected and despised, especially
socially.
- outcry n. A vehement or loud cry or clamor.
- outdo v. To surpass.
- outlandish adj. Of barbarous, uncouth, and unfamiliar aspect
or action.
- outlast v. To last longer than.
- outlaw n. A habitual lawbreaker.
- outlive v. To continue to exist after.
- out-of-the-way adj. Remotely situated.
- outpost n. A detachment of troops stationed at a distance from
the main body to guard against surprise.
- outrage n. A gross infringement of morality or decency.
- outrageous adj. Shocking in conduct.
- outreach v. To reach or go beyond.
- outride v. To ride faster than.
- outrigger n. A part built or arranged to project beyond a
natural outline for support.
- outright adv. Entirely.
- outskirt n. A border region.
- outstretch v. To extend.
- outstrip v. To go beyond.
- outweigh v. To surpass in importance or excellence.
- overdo v. To overtax the strength of.
- overdose n. An excessive dose, usually so large a dose of a
medicine that its effect is toxic.
- overeat v. To eat to excess.
- overhang n. A portion of a structure which projects or hangs
over.
- overleap v. To leap beyond.
- overlord n. One who holds supremacy over another.
- overpass v. To pass across or over, as a river.
- overpay v. To pay or reward in excess.
- overpower v. To gain supremacy or victory over by superior
power.
- overproduction n. Excessive production.
- overreach v. To stretch out too far.
- overrun v. To infest or ravage.
- oversee v. To superintend.
- overseer n. A supervisor.
- overshadow v. To cast into the shade or render insignificant
by comparison.
- overstride v. To step beyond.
- overthrow v. To vanquish an established ruler or
government.
- overtone n. A harmonic.
- overture n. An instrumental prelude to an opera, oratorio, or
ballet.
- overweight n. Preponderance.