"checkmates" in the noun sense
1. checkmate
complete victory
2. checkmate, mate
a chess move constituting an inescapable and indefensible attack on the opponent's king
"checkmates" in the verb sense
1. checkmate, mate
place an opponent's king under an attack from which it cannot escape and thus ending the game
"Kasparov checkmated his opponent after only a few moves"
Source: WordNet® (An amazing lexical database of English)
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