The Collaborative International Dictionary of English v.0.48:

Hot-headed \Hot"-head`ed\, a.
   quickly and easily aroused to anger; fiery; violent; rash;
   hasty; impetuous; vehement; as, a hot-headed commander.
   [WordNet sense 1] --Macaulay.

   Syn: choleric, irascible, hotheaded, hot-tempered,
        quick-tempered, short-tempered.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

hotheaded \hotheaded\ adj.
   1. same as hot-headed.

   Syn: choleric, irascible, hot-headed, hot-tempered,
        quick-tempered, short-tempered.
        [WordNet 1.5]

   2. liable to act with undue haste and without consideration.

   Syn: brainish, impulsive, impetuous, madcap,
        tearaway(prenominal).
        [WordNet 1.5]

Moby Thesaurus II by Grady Ward, 1.0:

64 Moby Thesaurus words for "hotheaded":
   accident-prone, ardent, brash, breakneck, careless, combustible,
   daredevil, desperate, devil-may-care, explosive, fanatic, fierce,
   fiery, flaming, foolhardy, furious, hard-core, harum-scarum, hasty,
   headlong, heated, heedless, hot, hot-tempered, hurried,
   ill-advised, impetuous, incautious, inconsiderate, inflamed, mad,
   madcap, overeager, overenthusiastic, overzealous, passionate,
   peppery, precipitant, precipitate, precipitous, quick,
   quick-tempered, rash, reckless, red-hot, scorching, short-tempered,
   simmering, slap-bang, slapdash, spunky, stormy, tempestuous,
   thoughtless, tornadic, totally committed, vehement, violent,
   volatile, volcanic, wanton, white-hot, wild, zealous