Coup de grâce

phrase/kuː də ɡɹɑs/foreign

Definition

A final blow that ends something; a death blow or knockout punch.

Etymology

First use appears c. 1699. Borrowed from French coup de grâce (“finishing blow”). Originally referring to a merciful stroke putting a fatally wounded person out of misery or to the shot delivered to the head of a prisoner after facing a firing squad.

In a sentence

The audit findings were the coup de grâce for the failing vendor relationship.