Definition of "cutthroat"

A murderer who slits the throats of victims.  examples

An unscrupulous, ruthless or unethical person.  examples

(uncountable) A three-player pocket billiards game where the object is to be the last player with at least one ball still on the table.  examples

Involving the cutting of throats.  examples

Of or relating to a card game where everyone plays for him or herself rather than playing with a partner.  examples

Ruthlessly competitive, dog-eat-dog.  examples