THESAURUS
Occasion
a leg up, advantage, adventure, affair, antecedent, antecedents, author, bare necessities, base, basis, bear, beget, break, breed, bring about, bring forth, bring on, bring to effect, bring to pass, call, call for, call forth, call up, causation, cause, cause and effect, celebration, ceremony, chance, circumstance, clear stage, commemoration, conceive, condition, conjuncture, contingency, create, demand, demand for, desideration, desideratum, determinant, determinative, do, effect, effectuate, element, elicit, engender, episode, essential, essentials, establish, etiology, event, eventuality, evoke, excuse, experience, fact, factor, fair field, fair game, father, found, foundation, function, gala, generate, gestate, give birth to, give occasion to, give origin to, give rise to, go, ground, grounds, hap, happening, happenstance, impel, impulse, inaugurate, incident, incitement, indispensable, induce, inducement, institute, juncture, justification, liberty, look-in, make, make for, matter of fact, milestone, moment, must, must item, necessaries, necessities, necessity, need, need for, obligation, observance, occasionally, occurrence, on occasion, opening, opportunism, opportunity, originate, particular, party, phenomenon, place, prerequirement, prerequisite, principle, produce, prompt, prompting, provocation, provoke, reality, realize, reason, requirement, requisite, requisition, right, room, scope, set afloat, set on foot, set up, shot, show, sire, squeak, stepping-stone, stimulus, the necessary, the needful, thing, time, turn of events, want, warrant, work, work up
ROGET THESAURUS
Occasion
Circumstance
N
circumstance, situation, phase, position, posture, attitude, place, point, terms, regime, footing, standing, status, occasion, juncture, conjunctive, contingency, predicament, emergence, emergency, exigency, crisis, pinch, pass, push, occurrence, turning point, bearings, how the land lies, surroundings, context, environment, location, contingency, dependence (uncertainty), causation, attribution, circumstantial, given, conditional, provisional, critical, modal, contingent, incidental, adventitious, limitative, in the circumstances, under the circumstances, the circumstances, conditions, thus, in such wise, accordingly, that being the case, such being the case, in view of the circumstances, that being so, sith, since, seeing that, as matters stand, as things go, as times go, conditionally, provided, if, in case, if so, if so be, if it be so, depending on circumstances, in certain circumstances, under certain conditions, if it so happen, if it so turn out, in the event of, in such a contingency, in such a case, in such an event, provisionally, unless, without, according to circumstances, according to the occasion, as it may happen, as it may turn out, as it may be, as the case may be, as the wind blows, pro re nata, yet are my sins not those of circumstance.
Occasion
N
timeliness, occasion, opportunity, opening, room, event (eventuality), suitable season, proper season, suitable time, proper time, high time, opportuneness, tempestivity, crisis, turn, juncture, conjuncture, crisis, turning point, given time, nick of time, golden opportunity, well timed opportunity, fine opportunity, favorable opportunity, opening, clear stage, fair field, mollia tempora, fata Morgana, spare time, opportune, timely, well-timed, timeful, seasonable, providential, lucky, fortunate, happy, favorable, propitious, auspicious, critical, suitable, obiter dicta, opportunely, in proper course, in due course, in proper season, in due season, in proper time, in due time, for the nonce, in the nick of time, in the fullness of time, all in good time, just in time, at the eleventh hour, now or never, by the way, by the by, en passant, a propos, pro re nata, pro hac vice, par parenthese, parenthetically, by way of parenthesis, incidentally, while speaking of, while on the subject, extempore, on the spur of the moment, on the spur of the occasion, on the spot, carpe diem occasionem cognosce, one's hour is come, the time is up, that reminds me, now that you mention it, come to think of it, bien perdu bien connu, e sempre l'ora, ex quovis ligno non fit Mercurius, nosce tempus, nunc aut nunquam.
Cause
N
cause, origin, source, principle, element, occasioner, prime mover, primum mobile, vera causa, author, mainspring, agent, leaven, groundwork, foundation, spring, fountain, well, font, fountainhead, spring head, wellhead, fons et origo, genesis, descent, remote cause, influence, pivot, hinge, turning point, lever, crux, fulcrum, key, proximate cause, causa causans, straw that breaks the camel's back, ground, reason, reason why, why and wherefore, rationale, occasion, derivation, final cause, les dessous des cartes, undercurrents, rudiment, egg, germ, embryo, bud, root, radix radical, etymon, nucleus, seed, stem, stock, stirps, trunk, tap-root, gemmule, radicle, semen, sperm, nest, cradle, nursery, womb, nidus, birthplace, hotbed, causality, causation, origination, production, caused, causal, original, primary, primitive, primordial, aboriginal, protogenal, radical, embryonic, embryotic, in embryo, in ovo, seminal, germinal, at the bottom of, connate, having a common origin, because, behind the scenes, causa latet vis est notissima, felix qui potuit rerum cognoscere causas.
VB
be the cause of, originate, give origin to, give rise, to, give occasion to, cause, occasion, sow the seeds of, kindle, suscitate, bring on, bring to bring pass, bring about, produce, create, set up, set afloat, set on foot, found, broach, institute, lay the foundation of, lie at the root of, procure, induce, draw down, open the door to, superinduce, evoke, entail, operate, elicit, provoke, conduce to, contribute, have a hand in the pie, have a finger in the pie, determine, decide, turn the scale, have a common origin, derive its origin.