Meaning

noun complete victory

noun a chess move constituting an inescapable and indefensible attack on the opponent's king

verb place an opponent's king under an attack from which it cannot escape and thus ending the game

originFrom Middle English chekmat, from Old French eschec mat, from Arabic شَاه مَاتَ (šāh māta), from Classical Persian شاه مات (šāh māt, “the king [is] amazed”).

Etymology from Wiktionary, CC BY-SA 3.0