Meanings
How to pronounce "knock out":
AU
To strike or bump (someone or something) out.
Example: "I accidentally knocked out the glass in my picture frame."
To render unconscious, as by a blow to the head.
Example: "The boxer knocked out his opponent in the third round."
To put to sleep.
Example: "The allergy pill knocked him out for a good three hours."
To fall asleep, especially suddenly.
To exhaust.
Example: "Running errands all day really knocked him out."