The story
- French · borrowed fromcoup de grâce“finishing blow”
- English todaycoup de grâce
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.
Etymology from Wiktionary, CC BY-SA 4.0.