WordNet sense 1 (a cruelly rapacious person):

beast, savage, wildcat, wolf

WordNet sense 2 (resembling a beast; showing lack of human sensibility):

beastly, bestial, brutish

WordNet sense 3 (lacking and reflecting lack of pity or compassion):

inhumane

WordNet sense 4 (a living organism characterized by voluntary movement):

animal, creature, fauna, animate being