The expression coup de grâce ( /ˌkuː də ˈɡrɑːs/; French: [ku də ɡʁɑs], “blow of mercy”) means a death blow intended to end the suffering of a wounded creature. The phrase can refer to the killing of civilians or soldiers, friends or enemies, with or without the consent of the sufferer.
It is often used figuratively to describe the last in a series of events which brings about the end of some entity; for example: “The business had been failing for years; the coup de grâce was the sudden jump in oil prices.
In the context of an execution, it means shooting the heart or head (typically the back of the skull) of an already wounded, but not yet dead, person during a military or civilian execution. It can also refer to the near beheading that follows a samurai’s seppuku.
In wartime, it can also be used to refer to the shooting (or other killing) of a seriously wounded person, either friendly or enemy, who is not expected to live or for whom medical aid cannot be obtained.
In countries that authorize executions by firing squads, a coup de grâce can be administered if the first hail of gunfire fails to kill the prisoner.