To fall asleep, especially suddenly.
To lose the scent of hounds in fox-hunting.
To eliminate from a contest or similar.
To put to sleep.
To complete, especially in haste; knock off.
To render unconscious, as by a blow to the head.
To strike or bump (someone or something) out.
To exhaust.
To cause a mechanism to become non-functional by damaging or destroying it.
To communicate (a message) by knocking.