The Collaborative International Dictionary of English v.0.48:

Bloodthirsty \Blood"thirst`y\, a.
   Eager to shed blood; cruel; sanguinary; murderous; having a
   bloodlust. -- Blood"thirst`i*ness (?), n.
   [1913 Webster]

WordNet (r) 3.0 (2006):

bloodthirsty
    adj 1: marked by eagerness to resort to violence and bloodshed;
           "bloody-minded tyrants"; "bloodthirsty yells"; "went
           after the collaborators with a sanguinary fury that
           drenched the land with blood"-G.W.Johnson [syn:
           bloodthirsty, bloody-minded, sanguinary]

Moby Thesaurus II by Grady Ward, 1.0:

96 Moby Thesaurus words for "bloodthirsty":
   Draconian, Tartarean, aggressive, animal, antagonistic,
   anthropophagous, atrocious, barbaric, barbarous, battling, beastly,
   bellicose, belligerent, bestial, bloody, bloody-minded, brutal,
   brutalized, brute, brutish, cannibalistic, chauvinist,
   chauvinistic, combative, contentious, cruel, cruel-hearted,
   cutthroat, demoniac, demoniacal, devilish, diabolic, enemy, fell,
   feral, ferocious, fiendish, fiendlike, fierce, fighting,
   full of fight, gory, hawkish, hellish, homicidal, hostile,
   infernal, inhuman, inhumane, inimical, jingo, jingoish, jingoist,
   jingoistic, martial, militant, militaristic, military, murdering,
   murderous, offensive, pitiless, pugnacious, quarrelsome,
   red-handed, ruthless, saber-rattling, sadistic, sanguinary,
   sanguine, sanguineous, satanic, savage, scrappy, self-destructive,
   sharkish, slaughterous, slavering, soldierlike, soldierly,
   subhuman, suicidal, trigger-happy, truculent, unchristian,
   uncivilized, unfriendly, unhuman, unpacific, unpeaceable,
   unpeaceful, vicious, warlike, warmongering, warring, wolfish