GRE Word List O(part 1)

oaf stupid awkward person; CF. elf
oath solemn promise; blasphemous use of sacred words to express strong feelings; swear-word; Ex. “For Christ’s sake'’
oatmeal crushed oats used for making porridge
obdurate stubborn; refusing to change one’s belief
obeisance bow (to show respect and obedience)
obelisk tall column tapering(becoming gradually narrower toward the end) and ending in a pyramid
obese excessively fat; N. obesity
obfuscate confuse; muddle; cause confusion; make needlessly complex; make so confused as to be difficult to understand
obituary death notice (esp. in a newspaper); ADJ.
objective not influenced by emotions; fair; N: goal; aim
obligatory binding; required; compulsory; V. oblige: constrain; make grateful; do a favor; accommodate
oblique indirect; slanting (deviating from the perpendicular or from a straight line); Ex. oblique reference
obliterate destroy completely; wipe out; Ex. obliterate the village
oblivion obscurity; condition of being completely forgotten; forgetfulness
oblivious inattentive or unmindful; unaware; wholly absorbed; forgetful(having the habit of forgetting)
obloquy slander; disgrace; infamy
obnoxious offensive; disagreeable; Ex. obnoxious smell
obscure dark; vague; unclear; not well known; Ex. obscure meaning/village; V: darken; cover; make unclear; Ex. obscure the moon/meaning
obsequious slavishly attentive; servile; full of servile compliance; sycophantic
obsequy funeral ceremony
obsessive related to thinking about something constantly; of an obsession; preoccupying; N. obsession: compulsive preoccupation with a fixed idea; compulsive idea; V. obsess: preoccupy the mind of excessively
obsidian black volcanic rock
obsolete outmoded; no longer used
obstetrician physician specializing in delivery(assisting in giving birth) of babies; N. obstetrics; CF. midwife
obstinate stubborn; hard to control or treat; Ex. obstinate cough; N. obstinacy
obstreperous boisterous; noisy and uncontrollable
obtrude push (oneself or one’s ideas) forward or intrude; impose (oneself or one’s ideas) on others; butt in; stick out or extrude; thrust out; Ex. obtrude A on B; ADJ. obtrusive; N. obtrusion; CF. unobtrusive
obtuse blunt; not sharp; stupid; slow in understanding
obviate make unnecessary; get rid of; Ex. obviate the need
Occident the West
occlude shut; close; obstruct; Ex. A blood clot occluded an artery.
occult mysterious; secret; supernatural; beyond human comprehension; CF. mysterious to human ?; OP. bare
oculist physician who specializes in treatment of the eyes
odds chances; probability; disagreement; Ex. The odds are that it will rain. Ex. at odds with
odious arousing strong dislike; hateful(causing hatred); vile
odium detestation; quality of being odious; hatefulness; disrepute (resulting from hateful conduct)
odoriferous giving off an odor
odorous having an odor
odyssey long, eventful, adventurous journey
offensive attacking; insulting; distasteful; V. offend: violate; hurt the feelings of; N. offense: offending; violating of a moral or social code; crime; attack; Ex. first offense
offhand casual; done without prior thought or preparation
officious meddlesome; excessively pushy in offering one’s services; overly eager in offering unwanted services or advices; Ex. officious bellboy
ogle look at amorously; make eyes at; Ex. old men ogling young girls
olfactory concerning the sense of smell
oligarchy government by a privileged few
ominous threatening; of an evil omen
omnipotent all-powerful; having unlimited power
omnipresent universally present; ubiquitous
omniscient all-knowing
omnivorous eating both plant and animal food; devouring everything
onerous burdensome
onomatopoeia words formed in imitation of natural sounds
onslaught vicious assault; fierce attack; Ex. unexpected onslaught of the enemy
onus burden; responsibility
ooze (of a thick liquid) pass or flow slowly; N: mud or thick liquid as at the bottom of a river
opalescent iridescent; lustrous; like an opal; N. opalescence
opaque dark; not transparent; N. opacity
opiate medicine to induce sleep or deaden pain; something that relieves emotions or causes inaction; sleep-producing drug containing opium
opportune timely; well-chosen
opportunist individual who sacrifices principles for expediency by taking advantage of circumstances; N. opportunism
opprobrium infamy; disgrace arising from shameful conduct; vilification(slander); scorn; contempt; Ex. opprobrium hurled against him; ADJ. opprobrious: expressing contempt; shameful or infamous
optician maker and seller of eyeglasses
optimist person who looks on the bright side; N. optimism
optimum most favorable; optimal; N: most favorable condition
optional not compulsory; left to one’s choice; N. option: act of choosing; choice; freedom or power to choose; something available as a choice; Ex. have no option; Ex. two options
optometrist one who fits glasses to remedy visual defects