a person who cuts throats; murderer.

murderous.

ruthless

cutthroat competition.

pertaining to a game, as of cards, in which each of three or more persons acts and scores as an individual.

adjective

barbarous , bloodthirsty , cruel , dog-eat-dog * , ferocious , hard as nails , merciless , pitiless , relentless , savage , unprincipled , vicious , bloody , bloody-minded , homicidal , sanguinary , sanguineous , slaughterous , hoodlum , murderer , ruffian , ruthless

noun

butcher , homicide , killer , manslayer , massacrer , murderess , slaughterer , slayer , triggerman