THESAURUS
Sudden
aback, abrupt, abruptly, accelerated, breakneck, breathless, brisk, electrifying, expeditious, extraordinary, fast, fleet, forthwith, hasty, headlong, hurried, immediate, impatient, impetuous, improbable, impulsive, more than expected, nerve-shattering, out-of-the-way, overhasty, panting, past expectation, precipitant, precipitate, precipitous, quick, rapid, rash, reckless, rushing, shocking, short, speedy, startling, suddenly, surprising, swift, unannounced, unanticipated, unanticipatedly, unaware, undivined, unexpected, unexpectedly, unforeseeable, unforeseen, unguessed, unheralded, unhoped for, unlooked-for, unpredictable, unpredicted, unprepared for, unwonted, without warning
ROGET THESAURUS
Sudden
Transientness
N
transience, transientness, evanescence, impermanence, fugacity, caducity, mortality, span, nine days' wonder, bubble, Mayfly, spurt, flash in the pan, temporary arrangement, interregnum, velocity, suddenness, changeableness, transient, transient boarder, transient guest, transient, transitory, transitive, passing, evanescent, fleeting, cursory, short-lived, ephemeral, flying, fugacious, fugitive, shifting, slippery, spasmodic, instantaneous, momentaneous, temporal, temporary, provisional, provisory, deciduous, perishable, mortal, precarious, unstable, insecure, impermanent, brief, quick, brisk, extemporaneous, summary, pressed for time, sudden, momentary, temporarily, pro tempore, for the moment, for a time, awhile, en passant, in transitu, in a short time, soon, briefly, at short notice, on the point of, on the eve of, in articulo, between cup and lip, one's days are numbered, the time is up, here today and gone tomorrow, non semper erit aestas, eheu! fugaces labuntur anni, sic transit gloria mundi, a schoolboy's tale, the wonder of the hour!, dum loquimur fugerit invidia aetas, fugit hora, all that is transitory is but an illusion.
Instantaneity
N
instantaneity, instantaneousness, immediacy, suddenness, abruptness, moment, instant, second, minute, twinkling, trice, flash, breath, crack, jiffy, coup, burst, flash of lightning, stroke of time, epoch, time, time of day, time of night, hour, minute, very minute, very time, very hour, present time, right time, true time, exact correct time, instantaneous, momentary, sudden, immediate, instant, abrupt, discontinuous, precipitous, precipitant, precipitate, subitaneous, hasty, quick as thought, quick as lightning, quick as a flash, rapid as electricity, speedy, quick, fast, fleet, swift, lively, blitz, rapid (velocity), instantaneously, in no time, in less than no time, presto, subito, instanter, suddenly, at a stroke, like a shot, in a moment, in the blink of an eye, in the twinkling of an eye, in a trice, in one's tracks, right away, toute a l'heure, at one jump, in the same breath, per saltum, uno saltu, at once, all at once, plump, slap, at one fell swoop, at the same instant, immediately, extempore, on the moment, on the spot, on the spur of the moment, no sooner said than done, just then, slap-dash, touch and go, no sooner said than done.
Earliness
N
earliness, morning, punctuality, promptitude, haste, suddenness, prematurity, precocity, precipitation, anticipation, a stitch in time, early, prime, forward, prompt, summary, premature, precipitate, precocious, prevenient, anticipatory, rath, sudden, unexpected, near, near at hand, immediate, early, soon, anon, betimes, rath, eft, eftsoons, ere long, before long, shortly, beforehand, prematurely, precipitately, too soon, before its time, before one's time, in anticipation, unexpectedly, suddenly, before one can say 'Jack Robinson', at short notice, extempore, on the spur of the moment, on the spur of the occasion, at once, on the spot, on the instant, at sight, offhand, out of hand, a' vue d'oeil, straight, straightway, straightforth, forthwith, incontinently, summarily, immediately, briefly, shortly, quickly, speedily, apace, before the ink is dry, almost immediately, presently at the first opportunity, in no long time, by and by, in a while, directly, no sooner said than done, immediately, if not sooner, tout vient a temps pour qui sait attendre.
Inexpectation
N
inexpectation, non-expectation, false expectation, miscalculation, surprise, sudden burst, thunderclap, blow, shock, start, bolt out of the blue, wonder, eye opener, unpleasant surprise, pleasant surprise, nonexpectant, surprised, unwarned, unaware, off one's guard, inattentive, unexpected, unanticipated, unpredicted, unlooked for, unforeseen, unhoped for, dropped from the clouds, beyond expectation, contrary to expectation, against expectation, against all expectation, out of one's reckoning, unheard of, startling, surprising, sudden, unpredictable, unforeseeable (unknowable), abruptly, unexpectedly, surprisingly, plump, pop, a l'improviste, unawares, without notice, without warning, without a 'by your leave', like a thief in the night, like a thunderbolt, in an unguarded moment, suddenly, Int, heydey!, little did one think, little did one expect, nobody would ever suppose, nobody would ever think, nobody would ever expect, who would have thought? it beats the Dutch.