[check.mate] vt [ME chekmaten, fr. chekmate, interj. used to announce checkmate, fr. MF eschec mat, fr. Ar shah mat, fr. Per, lit., the king is left unable to escape] (14c) 1: to arrest, thwart, or counter completely
2: to check (a chess opponent's king) so that escape is impossible
[2]checkmate n (15c) 1 a: the act of checkmating b: the situation of a checkmated king
2: a complete check