coup de grâce
/ˌkuːdəˈgrɑːs, 〈法〉 ku də gʀas/noun
(pl. coups de grace. 读音同)
- a final blow or shot given to kill a wounded person or animal（给受伤的人或动物的）致命一击（或一枪）：
he administered the coup de grace with a knife
他砍了致命的最后一刀
figurative 〈喻〉the party won another term and delivered the coup de grace to the Opposition.
该党又赢得了一任, 给反对党以致命打击。
词源
French, literally 'stroke of grace'.