Definitions
1.NounA murderer who slits the throats of victims.
2.NounAn unscrupulous, ruthless or unethical person.
3.NounA three-player pocket billiards game where the object is to be the last player with at least one ball still on the table.
4.NounEllipsis of cutthroat compound (“an agentive-instrumental verb-noun compound word”).
5.AdjectiveInvolving the cutting of throats.
6.AdjectiveOf 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."
7.AdjectiveRuthlessly competitive, dog-eat-dog."Law is a cutthroat business, you always have to look out to see who is trying to outdo you."