cutthroat

[ kuht-throht ]
/ ˈkʌtˌθroʊt /

noun

a person who cuts the throat of another; a murderer.

adjective

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

Origin of cutthroat

First recorded in 1525–35; cut + throat