knock out

verb

To strike or bump (someone or something) out.

“The boxer knocked out his opponent in the third round.”

Similar
knock coldkayo
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Meanings

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

present singular third person knocks out · participle present knocking out · participle past knocked out · past knocked out

  1. To strike or render unconscious
    1. transitiveTo strike or bump (someone or something) out.

      I accidentally knocked out the glass in my picture frame.

    2. idiomatictransitiveTo render unconscious, as by a blow to the head.

      The boxer knocked out his opponent in the third round.

      1 more example

      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. idiomaticinformaltransitiveTo put to sleep.

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

    4. idiomaticinformalintransitiveTo 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. idiomaticinformaltransitiveTo exhaust.

      Running errands all day really knocked him out.

    6. idiomaticinformaltransitiveTo impress, surpass or overwhelm (someone).
    7. slangtransitiveTo defeat or kill (someone).
    8. idiomatictransitiveTo cause a mechanism to become non-functional by damaging or destroying it.

      The antitank gun knocked out the enemy tank.

    9. transitiveTo eliminate from a contest or similar.

      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
      1 more example

      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
  2. transitiveTo communicate (a message) by knocking.

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

  3. informaltransitiveTo complete, especially in haste; knock off.

    They knocked out the entire project in one night.

  4. To lose the scent of hounds in fox-hunting.
  5. obsoleteOxford University slangTo leave college after hours—after half-past ten at night when the doors have been locked.

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

    1861, Thomas Hughes, Tom Brown at Oxford, London: Macmillan and Co., published 1883, page 503
  6. AustraliatransitiveTo obtain or earn (something, often money or food).
  7. UKslangtransitiveTo sell.

Synonyms & antonyms

verbknock unconscious or senseless

Similar
knock coldkayo
Broader
beatbeat upwork over
Also see
grasskayoknock offput output someone's lights outring someone's bell

Synonym sets from Open English WordNet, CC BY 4.0.

Translations

Ancient Greek ἐκκρούω
  • ἐκκρούω (ekkroúō)to strike or bump something out
Chinese Mandarin 昏迷
  • 昏迷 (hūn mí)to render someone unconscious, as by a blow to the head
Finnish lyödä ulos, lyödä irti
  • lyödä ulosto strike or bump something out
  • lyödä irtito strike or bump something out
  • tyrmätäto render someone unconscious, as by a blow to the head
  • kolkatato render someone unconscious, as by a blow to the head
  • lyödä kanveesiinto render someone unconscious, as by a blow to the head
  • tyrmätäto put to sleep
  • nukuttaato put to sleep
  • hutaistato complete, especially in haste
  • sutaistato complete, especially in haste
  • tempaistato complete, especially in haste
French assommer, assommer
  • assommerto render someone unconscious, as by a blow to the head
  • assommerto put to sleep
Hungarian kiüt, eszméletlenre ver
  • kiütto render someone unconscious, as by a blow to the head
  • eszméletlenre verto render someone unconscious, as by a blow to the head
  • padlóra küld/viszto render someone unconscious, as by a blow to the head
  • knockoutolto render someone unconscious, as by a blow to the head
  • elaltatto put to sleep
  • kiütto put to sleep
  • elalszikto fall asleep, especially suddenly
  • elnyomja az álomto fall asleep, especially suddenly
  • tönkreteszto cause a mechanism to become non-functional by damaging or destroying it
  • kiejtto eliminate from a contest or similar
  • lekopogto communicate (a message) by knocking
  • összecsapto complete, especially in haste
Icelandic rota
  • rotato render someone unconscious, as by a blow to the head
Latin sōpiō
  • sōpiōto render someone unconscious, as by a blow to the head
Polish powalać, powalić
  • powalaćto strike or bump something out
  • powalićto strike or bump something out
  • powalaćto render someone unconscious, as by a blow to the head
  • powalićto render someone unconscious, as by a blow to the head
  • zwalać z nógto render someone unconscious, as by a blow to the head
  • zwalić z nógto render someone unconscious, as by a blow to the head
  • usypiaćto put to sleep
  • uśpićto put to sleep
  • zasypiaćto fall asleep, especially suddenly
  • zasnąćto fall asleep, especially suddenly
  • niszczyćto cause a mechanism to become non-functional by damaging or destroying it
  • zniszczyćto cause a mechanism to become non-functional by damaging or destroying it
Portuguese nocautear
  • nocautearto render someone unconscious, as by a blow to the head
Russian выбива́ть, вы́бить
  • выбива́ть (vybivátʹ)to strike or bump something out
  • вы́бить (výbitʹ)to strike or bump something out
  • нокаутировать (nokautirovatʹ)to render someone unconscious, as by a blow to the head
  • вырубить (vyrubitʹ)to render someone unconscious, as by a blow to the head
Spanish noquear
  • noquearto render someone unconscious, as by a blow to the head
Swedish knocka
  • knockato render someone unconscious, as by a blow to the head
Ukrainian нокаутува́ти
  • нокаутува́ти (nokautuváty)to render someone unconscious, as by a blow to the head
Cite this entry
APA

knock out. (n.d.). In WatkinsX Dictionary. Retrieved November 4, 2026, from https://dictionary.watkinsx.com/word/knock%20out

MLA

“knock out.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/knock%20out. Accessed November 4, 2026.

Chicago

WatkinsX Dictionary, s.v. “knock out,” accessed November 4, 2026, https://dictionary.watkinsx.com/word/knock%20out.

Source: knock out on Wiktionary, CC BY-SA 4.0.