from The American Heritage® Dictionary of the English Language, 4th Edition

  • transitive v. To strike with a hard blow.
  • transitive v. To affect in a specified way by striking hard: knocked the mugger senseless.
  • transitive v. To cause to collide: I knocked my head on a low beam.
  • transitive v. To produce by hitting or striking: knocked a hole in the wall.
  • transitive v. To instill with or as if with blows: We tried to knock some sense into his head.
  • transitive v. Slang To find fault with; criticize: Don't knock the food; it's free.
  • intransitive v. To strike a sharp audible blow or series of blows, as on a door.
  • intransitive v. To collide with something: knocked into the table.
  • intransitive v. To make a pounding or clanking noise: The car engine is knocking.
  • n. An instance of striking or colliding; a blow.
  • n. The sound of a sharp tap on a hard surface; a rap.
  • n. A pounding or clanking noise made by an engine, often as a result of faulty fuel combustion. Also called ping1.
  • n. Slang A cutting, often petty criticism.
  • around Informal To be rough or brutal with; maltreat.
  • around Informal To wander from place to place: knocking around Europe.
  • around Informal To discuss or consider: met to knock around some ideas.
  • knock back Informal To gulp (an alcoholic drink).
  • knock down To bring to the ground with a blow; topple.
  • knock down To disassemble into parts, as for storage or shipping.
  • knock down To declare sold at an auction, as by striking a blow with a gavel.
  • knock down Informal To reduce, as in price: knocked each radio down 20 percent.
  • knock down Slang To receive as wages; earn: knocks down $50 an hour.
  • knock off To take a break or rest from; stop: knocked off work at noon.
  • knock off To cease work: It's after five; let's knock off.
  • knock off Informal To complete, accomplish, or dispose of hastily or easily; finish: That author knocks off a book a year.
  • knock off Informal To get rid of; eliminate: knocked off 12 pounds in a month.
  • knock off Slang To kill or overcome.
  • knock off Slang To hold up or rob: knocked off a bank.
  • knock off Informal To copy or imitate, especially without permission: knocking off someone else's ideas.
  • knock out To render unconscious.
  • knock out Sports To defeat (a boxing opponent) by a knockout.
  • knock out To render useless or inoperative: The storm knocked out the phones.
  • knock out Informal To exert or exhaust (oneself or another) to the utmost: knocked herself out to be ready on time.
  • knock out Informal To produce in abundance: The workers knocked out 500 parts in one hour.
  • knock out To inactivate or remove (a gene) by genetic engineering.
  • knock together To make or assemble quickly or carelessly.
  • knock up Slang To make pregnant.
  • knock up Chiefly British To wake up or summon, as by knocking at the door.
  • knock up Chiefly British To wear out; exhaust.
  • idiom have it knocked Slang To be certain of success: "He knew he had it knocked after he saw a rough cut of Chinatown” ( Time).
  • idiom knock cold To render unconscious; knock out.
  • idiom knock dead To kill with a blow.
  • idiom knock dead Slang To affect strongly and positively: a performance that knocked the audience dead.
  • idiom knock it off Slang Quit it. Often used in the imperative: Knock it off! I'm trying to sleep.
  • idiom knock (oneself) out To make a great effort; exhaust oneself.
  • idiom knock out of the box Baseball To force the removal of (an opposing pitcher) by heavy hitting.
  • idiom the Slang To overwhelm or amaze.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. An abrupt rapping sound, as from an impact of a hard object against wood
  • n. An impact.
  • n. criticism
  • n. a batsman's innings.
  • n. Preignition, a type of abnormal combustion occurring in spark ignition engines caused by self-ignition or the characteristic knocking sound associated with it.
  • v. To rap one's knuckles against something, especially wood.
  • v. To bump or impact.
  • v. To denigrate, undervalue.
  • v. To pass, kick a ball towards another player.

from the GNU version of the Collaborative International Dictionary of English

  • n. A blow; a stroke with something hard or heavy; a jar.
  • n. A stroke, as on a door for admittance; a rap.
  • intransitive v. To drive or be driven against something; to strike against something; to clash.
  • intransitive v. To strike or beat with something hard or heavy; to rap
  • intransitive v. To practice evil speaking or fault-finding; to criticize habitually or captiously.
  • transitive v. To strike with something hard or heavy; to move by striking; to drive (a thing) against something
  • transitive v. To strike for admittance; to rap upon, as a door.
  • transitive v. To impress strongly or forcibly; to astonish; to move to admiration or applause.
  • transitive v. To criticise; to find fault with; to disparage.

from The Century Dictionary and Cyclopedia

  • To strike or beat; give a blow or blows to; hit; affect in some way by striking or hitting: as, to knock a ball with a bat; to knock a man senseless; he knocked me down; to knock out one's brains.
  • To use in striking; give a blow or blows with; bring into collision; dash: as, to knock the head against a post.
  • Nautical, to lay (a ship) on her side, as a gust or gale.
  • To accomplish hastily; put out of hand.
  • To deduct : as, to knock off ten cents from the price. [Colloq.l
  • In bookbinding, to make even the edges of, as a quantity of printed sheets, by striking them on a table while held loosely upright in the hands.
  • To construct hastily, as by nailing.
  • To strike a blow with the fist or with something hard or heavy; specifically, to rap upon a door or gate, as with the knuckles or a knocker, in order to attract the attention of those within.
  • To move or be moved so as to come in collision with something; strike; clash: as, one heavy body knocks against another; his knees knocked together from fright.
  • To smite upon the breast, as in penitence.
  • To die.
  • To speak ill of one.
  • See the extract.
  • To keep up a system of annoying attacks; to keep striking or hitting until the other side capitulates or buys the ‘knocker’ off.
  • n. A blow; a buffet; a stroke with the fist, or with anything hard or heavy, as a cudgel, a hammer, or the knocker of a door.
  • n. A clock.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • v. deliver a sharp blow or push :
  • n. negative criticism
  • v. rap with the knuckles
  • n. a vigorous blow
  • v. sound like a car engine that is firing too early
  • n. the act of hitting vigorously
  • n. the sound of knocking (as on a door or in an engine or bearing)
  • v. knock against with force or violence
  • v. find fault with; express criticism of; point out real or perceived flaws
  • n. a bad experience
  • v. make light, repeated taps on a surface


Middle English knokken, from Old English cnocian.
(American Heritage® Dictionary of the English Language, Fourth Edition)
Akin to Old Norse knoka (compare Swedish knocka, Danish knuge, to hug) and Middle High German knochen, to hit. (Wiktionary)


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