0 in boxing, the act of hitting the other fighter so that they fall to the ground and are unable to get up again within ten seconds: --
1 a competition in which only the winners of each stage play in the next stage, until one competitor or team is the final winner: --
a knockout competition/championship
The tournament is a straight knockout.
2 a person or thing that looks, sounds, etc. extremely attractive: --
3 extremely attractive: --
4 (in boxing) a situation in which a fighter falls after being hit and cannot get up in ten seconds: --
He won by a knockout in the tenth round.
5 a very attractive person or thing: --