abrupt, accident-prone, active, acute, adrift, afloat, aggressive, alternating, amorphous, animated, antsy-pantsy, antsy, anxious, ardent, breakneck, breathless, brisk, brittle, capricious, careless, chafing, changeable, changeful, corruptible, deciduous, desperate, desultory, deviable, devil-may-care, dizzy, dying, dynamic, eager, eccentric, edgy, electrifying, energetic, enterprising, enthusiastic, ephemeral, erratic, evanescent, excited, fading, fast and loose, fervid, fickle, fierce, fiery, fitful, fleeting, flickering, flighty, flitting, fluctuating, fly-by-night, flying, forceful, forcible, fragile, frail, freakish, fretful, fretting, fugacious, fugitive, full of pep, furious, giddy, go-go, harum-scarum, hasty, headlong, hearty, hopped-up, hotheaded, hurried, impassioned, impatient, impermanent, impulsive, in a lather, in a stew, in a sweat, incisive, inconsistent, inconstant, indecisive, infirm, insubstantial, intense, irregular, irresolute, irresponsible, keen, kinetic, lively, living, lusty, mad, mazy, mercurial, mettlesome, momentary, moody, mortal, mutable, nerve-shattering, nondurable, nonpermanent, offhand, on edge, overeager, overenthusiastic, overhasty, overzealous, panting, passing, passionate, peppy, perishable, precipitant, precipitate, precipitous, quick, rambling, rash, reckless, restive, restless, robust, roving, rushing, scatterbrained, shapeless, shifting, shifty, shocking, short-lived, shuffling, simmering, slap-bang, slapdash, smacking, snappy, spanking, spasmodic, speedy, spineless, spirited, spontaneous, spur-of-the-moment, squirming, squirmy, startling, stormy, strenuous, strong, sudden, surprising, swift, take-charge, take-over, tempestuous, temporal, temporary, tornadic, transient, transitive, transitory, trenchant, unaccountable, unanticipated, uncertain, uncontrolled, undependable, undisciplined, undurable, uneasy, unenduring, unexpected, unfixed, unforeseen, unlooked-for, unpatient, unplanned, unpredictable, unpredicted, unpremeditated, unquiet, unreflective, unreliable, unrestrained, unsettled, unstable, unstable as water, unstaid, unsteadfast, unsteady, unthinking, vacillating, vagrant, variable, vehement, vibrant, vicissitudinary, vicissitudinous, vigorous, violent, vivacious, vivid, volatile, volcanic, wandering, wanton, wavering, wavery, wavy, wayward, whimsical, wild, wishy-washy, zestful, zesty, zippy