THESAURUS
precipitous
abrupt, accident-prone, acclivitous, arduous, bluff, bold, breakneck, breathless, careless, declivitous, desperate, devil-may-care, electrifying, furious, harum-scarum, hasty, headlong, hotheaded, hurried, impetuous, impulsive, mad, nerve-shattering, orthodiagonal, orthogonal, overeager, overenthusiastic, overzealous, panting, perpendicular, plumb, plunging, precipitant, precipitate, quick, rapid, rash, reckless, right-angle, right-angled, right-angular, rushing, sharp, sheer, shocking, sideling, slap-bang, slapdash, speedy, startling, steep, stickle, straight-up, straight-up-and-down, sudden, surprising, swift, unanticipated, unexpected, unforeseen, unlooked-for, unpredicted, up-and-down, vertical, wanton, wild
ROGET THESAURUS
precipitous
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.