CUTTHROAT

A murderer who slits the throats of victims.

An unscrupulous, ruthless or unethical person.

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

Involving the cutting of throats

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

"He found that playing cutthroat Spades was much more difficult than playing with a partner."

Ruthlessly competitive, dog-eat-dog

"Law is a cutthroat business, you always have to look out to see who is trying to outdo you."