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 4293071:

     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, idiomatic) To put to sleep.

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

4. (intransitive, idiomatic) To fall asleep, especially suddenly.

   She knocks right out the minute she gets tucked in.

5. (transitive, 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, Hughes, Thomas, 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. […] "

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