Meaning of “knock sb out” - Learner’s Dictionary

knock sb out

phrasal verb with knock uk us /nɒk/ verb
MAKE UNCONSCIOUS

B2 to make someone become unconscious, usually by hitting them on the head:

He was knocked out halfway through the fight.
DEFEAT

B2 to defeat a person or team in a competition so they cannot take part any more:

(Definition of “knock sb out” from the Cambridge Learner’s Dictionary © Cambridge University Press)