a highly successful, unexpected stroke, act, or move; a clever action or accomplishment.
2.
(among the Plains Indians of North America) a brave or reckless deed performed in battle by a single warrior, as touching or striking an enemy warrior without sustaining injury oneself.
c.1400, from O.Fr. colp "to cut, strike," from M.L. colpus, from V.L. colapus, from L. colaphus "a cuff, box on the ear," from Gk. kolaphos "a blow, slap." Coup d'étate is 1646, from Fr., lit. "stroke of the state." Coup de grâce is 1699, lit. "stroke of grace."
Coup\ (k??), n. [F., fr.L. colaphus a cuff, Gr. ????.] A sudden stroke; an unexpected device or stratagem; -- a term used in various ways to convey the idea of promptness and force. Coup de grace (k??" de gr?s") [F.], the stroke of mercy with which an executioner ends by death the sufferings of the condemned; hence, a decisive, finishing stroke. Coup de main (k??` de m?n`) [F.] (Mil.), a sudden and unexpected movement or attack. Coup de soleil (k??` d s?-l?l or -l?"y') [F.] (Med.), a sunstroke. See Sunstroke. Coup d'['e]tat (k??" d?-t?") [F.] (Politics), a sudden, decisive exercise of power whereby the existing government is subverted without the consent of the people; an unexpected measure of state, more or less violent; a stroke of policy. Coup d'[oe]il (k[=oo]` d[~e]l"). [F.] (a) A single view; a rapid glance of the eye; a comprehensive view of a scene; as much as can be seen at one view. (b) The general effect of a picture. (c) (Mil.) The faculty or the act of comprehending at a glance the weakness or strength of a military position, of a certain arrangement of troops, the most advantageous position for a battlefield, etc.
Coup\ (k[=oo]), n. 1. A single roll of the wheel at roulette, or a deal at rouge et noir. [Cant] 2. Among some tribes of North American Indians, 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.