In war times, it means shooting into the cardiac or temporal region of an already shot, but not yet dead person during a military or civilian execution. It can also refer to the final destruction of an already sinking ship; during World War II, ships crippled beyond repair were often finished off by their own escorts, or by enemy submarines. Examples include the USS Wasp, the USS Lexington, and the USS Yorktown. It can also refer to the beheading that follows a samurai's seppuku.
In a classic duel to the death, if one combatant was wounded seriously enough that they were unlikely to survive, a coup de grâce would be performed.
The French pronunciation of the phrase is , but some English speakers mispronounce it as . Omitting the final "s" is an example of a hyperforeignism: in French, this mispronunciation sounds like coup de gras, which means "blow of fat", or cou de gras, which means "neck of fat." Furthermore, this confusion is compounded by the name "Mardi Gras."