The Collaborative International Dictionary of English v.0.48:

Hasty \Has"ty\ (h[=a]s"t[y^]), a. [Compar. Hastier
   (-t[i^]*[~e]r); superl. Hastiest.] [Akin to D. haastig, G.,
   Sw., & Dan. hastig. See Haste, n.]
   1. Involving haste; done, made, etc., in haste; as, a hasty
      retreat; a hasty sketch.
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   2. Demanding haste or immediate action. [R.] --Chaucer.
      "Hasty employment." --Shak.
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   3. Moving or acting with haste or in a hurry; hurrying;
      hence, acting without deliberation; precipitate; rash;
      easily excited; eager.
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            Seest thou a man that is hasty in his words? There
            is more hope of a fool than of him.   --Prov. xxix.
                                                  20.
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            The hasty multitude
            Admiring entered.                     --Milton.
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            Be not hasty to go out of his sight.  --Eccl. viii.
                                                  3.
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   4. Made or reached without deliberation or due caution; as, a
      hasty conjecture, inference, conclusion, etc., a hasty
      resolution.
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   5. Proceeding from, or indicating, a quick temper.
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            Take no unkindness of his hasty words. --Shak.
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   6. Forward; early; first ripe. [Obs.] "As the hasty fruit
      before the summer." --Is. xxviii. 4.
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WordNet (r) 3.0 (2006):

hasty
    adj 1: excessively quick; "made a hasty exit"; "a headlong rush
           to sell" [syn: hasty, headlong]
    2: done with very great haste and without due deliberation;
       "hasty marriage seldom proveth well"- Shakespeare; "hasty
       makeshifts take the place of planning"- Arthur Geddes;
       "rejected what was regarded as an overhasty plan for
       reconversion"; "wondered whether they had been rather
       precipitate in deposing the king" [syn: hasty, overhasty,
       precipitate, precipitant, precipitous]

Moby Thesaurus II by Grady Ward, 1.0:

191 Moby Thesaurus words for "hasty":
   a bit previous, abrupt, accident-prone, ad-lib, advanced, agile,
   antsy, antsy-pantsy, anxious, bearish, brash, breakneck,
   breathless, brief, brisk, careless, caught napping,
   caught off balance, caught short, chafing, choleric, combustible,
   contentious, cranky, cursory, dashing, desperate, devil-may-care,
   double-quick, eager, eagle-winged, edgy, electrifying, excited,
   expeditious, explosive, express, extemporaneous, extemporized,
   far ahead, fast, festinate, feverish, fiery, fleet, fleeting,
   flying, forward, fretful, fretting, furious, galloping,
   hair-trigger, half-baked, half-cocked, haphazard, harum-scarum,
   headlong, heedless, hopped-up, hot, hot-tempered, hotheaded,
   hurried, hustling, ill-advised, ill-considered, immediate,
   impatient, impetuous, impromptu, improvised, impulsive,
   in a lather, in a stew, in a sweat, incautious, inconsiderate,
   instant, instantaneous, irascible, irritable, last-minute,
   light of heel, light-footed, lively, mad, madcap, makeshift,
   mercurial, momentary, nerve-shattering, nimble, nimble-footed,
   not firm, on edge, on the spot, overeager, overenthusiastic,
   overhasty, oversoon, overzealous, passing, passionate, peppery,
   perfunctory, petulant, precipitant, precipitate, precipitous,
   precocious, premature, previous, prompt, quick, quick as lightning,
   quick as thought, quick-tempered, rapid, rash, reckless, restive,
   restless, rough-and-ready, running, rushed, rushing, shocking,
   short-tempered, slap-bang, slapdash, snap, snappy, spanking,
   speedy, splenetic, spunky, squirming, squirmy, startling, sudden,
   superficial, surprised, surprising, swift, taken aback,
   taken by surprise, taken unawares, testy, thoughtless, too early,
   too soon, tripped up, unanticipated, unarranged, unbegun,
   unconcocted, uncontrived, uncrystallized, undeliberated, undevised,
   uneasy, unexpected, unforeseen, unhatched, unjelled, unlooked-for,
   unmade, unmanufactured, unmatured, unmeditated, unorganized,
   unpatient, unplanned, unpredicted, unpremeditated, unprepared,
   unprimed, unquiet, unready, unripe, unstudied, unthinking,
   untimely, urgent, volatile, volcanic, wanton, waspish, wild,
   winged