knock out

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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. (transitive, idiomatic) To render unconscious, as by a blow to the head.

   The boxer knocked out his opponent in the third round.

   • 1918, W[illiam] B[abington] Maxwell, chapter XXII, in The Mirror and the Lamp, Indianapolis, Ind.: The Bobbs-Merrill Company, →OCLC:

     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.

3. (transitive, informal, idiomatic) To put to sleep.

   The allergy pill knocked him out for a good three hours.

4. (intransitive, informal, idiomatic) To fall asleep, especially suddenly.
   • 2014, D. G. Driver, Cry of the Sea, page 61:

     That's a put-you-straight-to-sleep book if there ever was one, and I knocked right out after two paragraphs.

5. (transitive, informal, idiomatic) To exhaust.

   Running errands all day really knocked him out.

6. (transitive, informal) To complete, especially in haste; knock off.

   They knocked out the entire project in one night.

7. (transitive, idiomatic) To cause a mechanism to become non-functional by damaging or destroying it.

   The antitank gun knocked out the enemy tank.

8. (transitive) To eliminate from a contest or similar.
   • 1980, InfoWorld, volume 2, number 20:

     As they were approaching bankruptcy from being knocked out of the calculator market, they began development on the first commercially available microcomputer, the Altair.

   • 2011 December 15, Marc Higginson, “Shamrock Rovers 0-4 Tottenham”, in BBC Sport:

     Tottenham were knocked out of the Europa League, despite a comfortable victory over Shamrock Rovers in Dublin.

9. (transitive) To communicate (a message) by knocking.

   The prisoner knocked out a message on the wall for the prisoner in the adjoining cell.

10. To lose the scent of hounds in fox-hunting.
11. (obsolete, Oxford University slang) To leave college after hours—after half-past ten at night when the doors have been locked.
    • 1861, Thomas Hughes, Tom Brown at Oxford, London: Macmillan and Co., published 1883, page 503:

      "Hullo!" he said, getting up; "time for me to knock out, or old Copas will be in bed. […] "

• knock one out
• knock oneself out → don't knock yourself out

• knockout
• (leave after hours): knock in (“enter after hours”)

• → Macedonian: нокаут (nokaut)
• → Portuguese: nocaute
• → Russian: нокаут (nokaut)
• → Serbo-Croatian: нокаут
• → Spanish: nocaut
• → Turkish: nakavt