The Collaborative International Dictionary of English v.0.48:

bitchy \bitchy\ adj.
   marked by or arising from malice. [slang]

   Syn: catty, cattish.
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

bitchy
    adj 1: marked by or arising from malice; "a catty remark" [syn:
           bitchy, catty, cattish]

Moby Thesaurus II by Grady Ward, 1.0:

75 Moby Thesaurus words for "bitchy":
   abusive, back-biting, baleful, bearish, belittling, calumniatory,
   calumnious, cankered, cantankerous, catty, censorious, churlish,
   contemptuous, contumelious, crabbed, cranky, cross, cross-grained,
   crusty, cussed, defamatory, deprecatory, depreciative,
   depreciatory, derisive, derisory, derogative, derogatory,
   despiteful, detractory, disagreeable, disparaging, evil, excitable,
   feisty, fractious, harmful, hateful, huffish, huffy, iniquitous,
   invidious, irascible, irritable, libelous, malefic, maleficent,
   malevolent, malicious, malign, malignant, mean, minimizing, nasty,
   noxious, ornery, pejorative, perverse, rancorous, ridiculing,
   scandalous, scurrile, scurrilous, slanderous, slighting, snappish,
   spiteful, spleeny, splenetic, testy, ugly, vicious, vilifying,
   waspish, wicked