What is the meaning of Knock_out?

To strike or bump (someone or something) out.

To render unconscious, as by a blow to the head.

To put to sleep.

To fall asleep, especially suddenly.

To exhaust.

To complete, especially in haste; knock off.

To cause a mechanism to become non-functional by damaging or destroying it.

To eliminate from a contest or similar.

To communicate (a message) by knocking.

To lose the scent of hounds in fox-hunting.

To leave college after hours—after half-past ten at night when the doors have been locked.

Source: wiktionary.org