omittance, n. omission, forbearance, default, neglect, oversight.

omnipresence, n. ubiquity.

omnipresent, n. ubiquitous.

one, n. unit. a.s.sociated Words: unify, unity, unification, numerary.

one after the other. _seriatim_; tandem; alternately, consecutively.

one hundred years. century, centenary. a.s.sociated Words: centenarian, centennial.

one letter. a.s.sociated Word: uniliteral.

on end. erect, perpendicular, upright.

oneness, n. unity, singleness, individuality, unanimity.

onerous, a. laborious, difficult, arduous.

one-sided, a. unilateral; partial, unfair, inequitable, _ex parte_.

one year. a.s.sociated Words: annual, annually.

on horseback. mounted.

onion, n. (that does not bottom out) scallion, eschallot, shallot.

a.s.sociated Words: alliaceous, cepaceous, leek, allium, garlic.

onlooker, n. looker-on, bystander, spectator, beholder, witness, eye-witness.

on tap. broached, abroached.

on the sly. (Collog.) sly, covertly, furtively, clandestinely, surrept.i.tiously, secretly.

ooze, v. filter, exude, percolate, transude, seep.

oozing, n. percolation, filtering, exudation, distillation, transudation.

opalescence, n. iridescence.

opalescent, a. iridescent.

opaque, a. intransparent; (Colloq.) obscure, unintelligible.

open, a. accessible, clear, un.o.bstructed, unrestricted; ajar, unlocked; extended, expanded, spread, gaping, yawning, unfolded, dehiscent; frank, unreserved, candid, ingenuous, guileless, overt, undisguised; generous, liberal, bounteous, open-handed; revealed, patent, manifest; unsettled, undetermined, debatable, undecided, controvertible; mild, clement; free, disengaged, unappropriated, unemployed.

open, v. spread, expand, unfold, evolve; reveal, disclose; unclose, unlock, unfasten; begin, commence; dehisce.

open-air, a. outdoor, al-fresco.

opening, a. beginning, introductory, initiatory, preliminary.

opening, n. aperture, fissure, gap, orifice, rift, chasm, hiatus, rent; beginning, introduction, outset; vacancy.

openly, adv. publicly, unreservedly, candidly.

open-mouthed, a. gaping, yawning; greedy, clamorous, ravenous, rapacious, eager.

opiate, n. narcotic, anodyne, sedative, dormitive, soporific.

opiate, a. somniferous, narcotic, anodyne, sedative, soporiferous, dormitive.

opinion, n. belief, judgment, impression; decision, ruling, verdict, sentence.

opium, n. a.s.sociated Words: narcotic, opiate, chandoo, thebaine, narcotine, codeine, dope, meconism, meconology, meconophagism, meconophagist, opiophagism.

opponent, n. adversary, antagonist, rival, compet.i.tor.

opportune, a. timely, seasonable, apropos, felicitous, appropriate.

oppose, v. combat, resist, confront, withstand, oppugn, impugn, contend, antagonize, contravene, discountenance, gainsay, contradict.

Antonyms: yield, acquiesce, concur, agree.

opposer, n. opponent, antagonist.

opposing, a. conflicting, antagonistic, contending, opposite, adverse.

opposite, n. ant.i.thesis, counterpart, antipodes.

opposite, a. contrary, adverse, diametrical, antagonistic, inverse, reverse, contradictory, counter, incompatible, ant.i.thetic, antipodal, inconsistent.

opposition, n. resistance, counteraction, hostility, repulse, rebuff, recalcitration, counterview, antagonism, contradiction, obstacle, impediment, obstruction. Antonyms: acquiescence, non-resistance, concurrence, agreement.

oppress, v. burden, overwhelm, aggrieve, tyrannize, persecute, overpower.

oppression, n. tyranny, persecution, extortion, hardship, severity.

oppressive, a. rigorous, tyrannical, extortionate, burdensome.

oppressor, n. tyrant, persecutor, extortioner.

option, n. choice, preference, election, discretion, alternative.

Antonyms: constraint, coercion, compulsion.

optional, a. discretional, elective. Antonyms: compulsory, coercive, obligatory.

oral, a. spoken, verbal, parole, vocal, nuncupative.