knock out

Verb

knock out (third-person singular simple present knocks out, present participle knocking out, simple past and past participle knocked out)

1. (transitive) To strike or bump (someone or something) out.
   • I accidentally knocked out the glass in my picture frame.
2. (idiomatic, transitive) To render unconscious, as by a blow to the head.
   • The boxer knocked out his opponent in the third round.
   • In the autumn there was a row at some cement works about the unskilled labour men. A union had just been started for them and all but a few joined. One of these blacklegs was laid for by a picket and knocked out of time.1918, W[illiam] B[abington] Maxwell, chapter XXII, in The Mirror and the Lamp, Indianapolis, Ind.: The Bobbs-Merrill Company, →OCLC
3. (idiomatic, informal, transitive) To put to sleep.
   • The allergy pill knocked him out for a good three hours.
4. (idiomatic, informal, intransitive) To fall asleep, especially suddenly.
   • That's a put-you-straight-to-sleep book if there ever was one, and I knocked right out after two paragraphs.2014, D. G. Driver, Cry of the Sea, page 61
5. (idiomatic, informal, transitive) To exhaust.
   • Running errands all day really knocked him out.
6. (idiomatic, informal, transitive) To impress, surpass or overwhelm (someone).
7. (slang, transitive) To defeat or kill (someone).
8. (idiomatic, transitive) To cause a mechanism to become non-functional by damaging or destroying it.
   • The antitank gun knocked out the enemy tank.
9. (transitive) To eliminate from a contest or similar.
   • As they were approaching bankruptcy from being knocked out of the calculator market, they began development on the first commercially available microcomputer, the Altair.1980, InfoWorld, volume 2, number 20
   • Tottenham were knocked out of the Europa League, despite a comfortable victory over Shamrock Rovers in Dublin.2011 December 15, Marc Higginson, “Shamrock Rovers 0-4 Tottenham”, in BBC Sport
10. (transitive) To communicate (a message) by knocking.
    • The prisoner knocked out a message on the wall for the prisoner in the adjoining cell.
11. (informal, transitive) To complete, especially in haste; knock off.
    • They knocked out the entire project in one night.
12. To lose the scent of hounds in fox-hunting.