Coup n.
1. A sudden stroke delivered with promptness and force; -- used also in various ways to convey the idea of an unexpected, clever, and successful tactic or stratagem.
2. A single roll of the wheel at roulette, or a deal at rouge et noir. [Cant]
3. Among some tribes of North American Indians especially of the Great Plains, the act of striking or touching an enemy in warfare with the hand or at close quarters, as with a short stick, in such a manner as by custom to entitle the doer to count the deed an act of bravery; hence, any of various other deeds recognized by custom as acts of bravery or honor.
While the coup was primarily, and usually, a blow with something held in the hand, other acts in warfare which involved great danger to him who performed them were also reckoned coups by some tribes. --G. B. Grinnell.
Among the Blackfeet the capture of a shield, bow, gun, war bonnet, war shirt, or medicine pipe was deemed a coup. --G. B. Grinnell.
Coup de grace
Coup de main
Coup de soleil
Coup d'état
Coup d'œil