- oakenadj.Made of or from oak
- oakumn.Hemp-fiber obtained by untwisting and picking out loosely the yarns of old hemp rope
- obdurateadj.Impassive to feelings of humanity or pity
- obeliskn.A square shaft with pyramidal top, usually monumental or commemorative
- obeseadj.Exceedingly fat
- obesityn.Excessive fatness
- obituaryadj.A published notice of a death
- objectiveadj.Grasping and representing facts as they are
- objectorn.One who objects, as to a proposition, measure, or ruling
- obligatev.To hold to the fulfillment of duty
- obligatoryadj.Binding in law or conscience
- obliqueadj.Slanting; said of lines
- obliteratev.To cause to disappear
- oblivionn.The state of having passed out of the memory or of being utterly forgotten
- oblongadj.Longer than broad: applied most commonly to rectangular objects considerably elongated
- obnoxiousadj.Detestable
- obsequiesn.Funeral rites
- obsequiousadj.Showing a servile readiness to fall in with the wishes or will of another
- observancen.A traditional form or customary act
- observantadj.Quick to notice
- observatoryn.A building designed for systematic astronomical observations
- obsolescencen.The condition or process of gradually falling into disuse
- obsolescentadj.Passing out of use, as a word
- obsoleteadj.No longer practiced or accepted
- obstetriciann.A practitioner of midwifery
- obstetricsn.The branch of medical science concerned with the treatment and care of women during pregnancy
- obstinacyn.Stubborn adherence to opinion, arising from conceit or the desire to have one's own way
- obstreperousadj.Boisterous
- obstructv.To fill with impediments so as to prevent passage, either wholly or in part
- obstructionn.Hindrance
- obtrudev.To be pushed or to push oneself into undue prominence
- obtrusiveadj.Tending to be pushed or to push oneself into undue prominence
- obvertv.To turn the front or principal side of (a thing) toward any person or object
- obviatev.To clear away or provide for, as an objection or difficulty
- occasionn.An important event or celebration
- Occidentn.The countries lying west of Asia and the Turkish dominions
- occludev.To absorb, as a gas by a metal
- occultadj.Existing but not immediately perceptible
- occupantn.A tenant in possession of property, as distinguished from the actual owner
- occurrencen.A happening
- octagonn.A figure with eight sides and eight angles
- octaven.A note at this interval above or below any other, considered in relation to that other
- octavon.A book, or collection of paper in which the sheets are so folded as to make eight leaves
- octogenarianadj.A person of between eighty and ninety years
- ocularadj.Of or pertaining to the eye
- oculistn.One versed or skilled in treating diseases of the eye
- oddityn.An eccentricity
- oden.The form of lyric poetry anciently intended to be sung
- odiousadj.Hateful
- odiumn.A feeling of extreme repugnance, or of dislike and disgust
- odoriferousadj.Having or diffusing an odor or scent, especially an agreeable one
- odorousadj.Having an odor, especially a fragrant one
- offadj.Farther or more distant
- offhandadv.Without preparation
- officiatev.To act as an officer or leader
- officiousadj.Intermeddling with what is not one's concern
- offshootn.Something that branches off from the parent stock
- ogren.A demon or monster that was supposed to devour human beings
- ointmentn.A fatty preparation with a butter-like consistency in which a medicinal substance exists
- olfactoryadj.of or pertaining to the sense of smell
- olive-branchn.A branch of the olive-tree, as an emblem of peace
- ominousadj.Portentous
- omissionn.Exclusion
- omnipotencen.Unlimited and universal power
- Omnipotentadj.Possessed of unlimited and universal power
- omnisciencen.Unlimited or infinite knowledge
- omniscientadj.Characterized by unlimited or infinite knowledge
- omnivorousadj.Eating or living upon food of all kinds indiscriminately
- onerousadj.Burdensome or oppressive
- onrushn.Onset
- onsetn.An assault, especially of troops, upon an enemy or fortification
- onslaughtn.A violent onset
- onusn.A burden or responsibility
- opalescencen.The property of combined refraction and reflection of light, resulting in smoky tints
- opaqueadj.Impervious to light
- operatev.To put in action and supervise the working of
- operativeadj.Active
- operatorn.One who works with or controls some machine or scientific apparatus
- operettan.A humorous play in dialogue and music, of more than one act
- opinionn.A conclusion or judgment held with confidence, but falling short of positive knowledge
- opponentn.One who supports the opposite side in a debate, discussion, struggle, or sport
- opportuneadj.Especially fit as occurring, said, or done at the right moment
- opportunistn.One who takes advantage of circumstances to gain his ends
- opportunityn.Favorable or advantageous chance or opening
- oppositeadj.Radically different or contrary in action or movement
- opprobriumn.The state of being scornfully reproached or accused of evil
- opticn.Pertaining to the eye or vision
- opticiann.One who makes or deals in optical instruments or eye-glasses
- opticsn.The science that treats of light and vision, and all that is connected with sight
- optimismn.The view that everything in nature and the history of mankind is ordered for the best
- optionn.The right, power, or liberty of choosing
- optometryn.Measurement of the powers of vision
- opulencen.Affluence
- opulentadj.Wealthy
- oraladj.Uttered through the mouth
- oratev.To deliver an elaborate or formal public speech
- orationn.An elaborate or formal public speech
- oratorn.One who delivers an elaborate or formal speech
- oratorion.A composition for solo voices, chorus, and orchestra, generally taken from the Scriptures
- oratoryn.The art of public speaking
- ordealn.Anything that severely tests courage, strength, patience, conscience, etc
- ordinaln.That form of the numeral that shows the order of anything in a series, as first, second, third
- ordinationn.A consecration to the ministry
- ordnancen.A general name for all kinds of weapons and their appliances used in war
- orgiesn.Wild or wanton revelry
- originn.The beginning of that which becomes or is made to be
- originaladj.Not copied nor produced by imitation
- originatev.To cause or constitute the beginning or first stage of the existence of
- ornateadj.Ornamented to a marked degree
- orthodoxadj.Holding the commonly accepted faith
- orthodoxyn.Acceptance of the common faith
- orthogonaladj.Having or determined by right angles
- orthopedicadj.Relating to the correcting or preventing of deformity
- orthopedistn.One who practices the correcting or preventing of deformity
- oscillatev.To swing back and forth
- osculatev.To kiss
- ossifyv.to convert into bone
- ostentationn.A display dictated by vanity and intended to invite applause or flattery
- ostracismn.Exclusion from intercourse or favor, as in society or politics
- ostracizev.To exclude from public or private favor
- oughtv.To be under moral obligation to be or do
- oustv.To eject
- out-and-outadv.Genuinely
- outbreakn.A sudden and violent breaking forth, as of something that has been pent up or restrained
- outburstn.A violent issue, especially of passion in an individual
- outcastn.One rejected and despised, especially socially
- outcryn.A vehement or loud cry or clamor
- outdov.To surpass
- outlandishadj.Of barbarous, uncouth, and unfamiliar aspect or action
- outlastv.To last longer than
- outlawn.A habitual lawbreaker
- outlivev.To continue to exist after
- out-of-the-wayadj.Remotely situated
- outpostn.A detachment of troops stationed at a distance from the main body to guard against surprise
- outragen.A gross infringement of morality or decency
- outrageousadj.Shocking in conduct
- outreachv.To reach or go beyond
- outridev.To ride faster than
- outriggern.A part built or arranged to project beyond a natural outline for support
- outrightadv.Entirely
- outskirtn.A border region
- outstretchv.To extend
- outstripv.To go beyond
- outweighv.To surpass in importance or excellence
- overdov.To overtax the strength of
- overdosen.An excessive dose, usually so large a dose of a medicine that its effect is toxic
- overeatv.To eat to excess
- overhangn.A portion of a structure which projects or hangs over
- overleapv.To leap beyond
- overlordn.One who holds supremacy over another
- overpassv.To pass across or over, as a river
- overpayv.To pay or reward in excess
- overpowerv.To gain supremacy or victory over by superior power
- overproductionn.Excessive production
- overreachv.To stretch out too far
- overrunv.To infest or ravage
- overseev.To superintend
- overseern.A supervisor
- overshadowv.To cast into the shade or render insignificant by comparison
- overstridev.To step beyond
- overthrowv.To vanquish an established ruler or government
- overtonen.A harmonic
- overturen.An instrumental prelude to an opera, oratorio, or ballet
- overweightn.Preponderance