WordNet (r) 3.0 (2006):

quick-tempered
    adj 1: quickly aroused to anger; "a hotheaded commander" [syn:
           choleric, irascible, hotheaded, hot-tempered,
           quick-tempered, short-tempered]

Moby Thesaurus II by Grady Ward, 1.0:

22 Moby Thesaurus words for "quick-tempered":
   abrupt, bad-tempered, choleric, churlish, excitable, hot-blooded,
   hot-tempered, ill-tempered, impatient, impulsive, irascible,
   irritable, quarrelsome, short, short-tempered, snappish, splenetic,
   temperamental, testy, touchy, volatile, waspish