coup (n.) Look up coup at Dictionary.com
c.1400, from Old French coup, colp "a blow, strike" (12c.), from Medieval Latin colpus, from Vulgar Latin colapus, from Latin colaphus "a cuff, box on the ear," from Greek kolaphos "a blow, slap." Meaning "a sudden decisive act" is 1852, short for coup d'etat. In Modern French the word is a workhorse, describing everything from a pat on the back to a whipping, and is used as well of thunder, gusts of wind, gunshots, and chess moves.