The Oxford Thesaurus An A-Z Dictionary of Synonyms - sanguinaryadj.

1) bloodthirsty, cruel, brutal, brutish, gory, merciless, remorseless, ruthless, pitiless, heartless, savage, barbarous, slaughterous, grim, fell, murderous, homicidal: The axe murder was the most sanguinary crime that the division had ever been required to investigate. 2) bloody, sanguineous, sanguinolent: I am unsure how I survived such a sanguinary battle.