have it knocked, Slang. to be assured of success: With a government job, he thought he had it knocked.
    knock out of the box, Baseball. to cause a pitcher to be removed from the box because the pitcher has permitted too many hits to be made.Also knock out.
    knock the/one's socks off, Informal. to have an overwhelming effect on: The song knocked the socks off the audience.

Origin of knock

before 1000; 1890–95 for def 4; Middle English knokken, knoken (v.), Old English cnocian, cnucian; cognate with Old Norse knoka to thump, knock
Related formsknock·less, adjectivere·knock, verbun·knocked, adjectiveun·knock·ing, adjective

Synonyms for knock

1. See strike. Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

British Dictionary definitions for knock down

knock down

verb (tr, adverb)

to strike to the ground with a blow, as in boxing
(in auctions) to declare (an article) sold, as by striking a blow with a gavel
to demolish
to dismantle, for ease of transport
informal to reduce (a price, etc)
Australian slang to spend (a cheque)
Australian slang to drink

adjective knockdown (prenominal)

overwhelming; powerfula knockdown blow
mainly British cheapI got the table at a knockdown price
easily dismantledknockdown furniture

noun knockdown

US and Australian slang an introductionwill you give me a knockdown to her?



(tr) to give a blow or push to; strike
(intr) to rap sharply with the knuckles, a hard object, etc, esp to capture attentionto knock at the door
(tr) to make or force by strikingto knock a hole in the wall
(intr usually foll by against) to collide (with)
(tr) to bring into a certain condition by hitting or pushingto knock someone unconscious
(tr) informal to criticize adversely; belittleto knock someone's work
Also: pink (intr) (of an internal-combustion engine) to emit a characteristic metallic noise as a result of faulty combustion
(intr) (of a bearing, esp one in an engine) to emit a regular characteristic sound as a result of wear
British slang to have sexual intercourse with (a person)
knock a person into the middle of next week informal to hit a person with a very heavy blow
knock one's head against to have a violent or unpleasant encounter with (adverse facts or circumstances)
knock on the head
  1. to daze or kill (a person) by striking on the head
  2. effectively to prevent the further development of (a plan)


  1. a blow, push, or raphe gave the table a knock
  2. the sound so caused
the sound of knocking in an engine or bearing
informal a misfortune, rebuff, or setback
informal unfavourable criticism
informal (in cricket) an innings or a spell of batting

Word Origin for knock

Old English cnocian, of imitative origin; related to Old Norse knoka to hit
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for knock down



Old English cnocian (West Saxon cnucian), "to pound, beat; knock (on a door)," likely of imitative origin. Meaning "deprecate, put down" is from 1892. Related: Knocked; knocking. Knock-kneed first attested 1774. Knock-down, drag-out is from 1827. Command knock it off "stop it" is first recorded 1880, perhaps from auctioneer's term for "dispose of quickly:"

At the commencement of the sales, he gave every one that wanted to purchase a paper containing a description of the lands that were to be sold; and, as the sales were cried, he called over the numbers and described the land; and when it got up to one dollar and a quarter an acre, if no body bid, after it was cried two or three times, he would say, knock it off, knock it off. [U.S. Senate record, 1834]



mid-14c., from knock (v.). As an engine noise, from 1899.

Online Etymology Dictionary, © 2010 Douglas Harper

Idioms and Phrases with knock down

knock down


Take apart for storage or shipping, as in We need to knock down this chest to ship it safely overseas. [Mid-1900s]


Declare sold at an auction, as by striking a blow with a gavel. For example, That was the last bid, and the first edition was knocked down for only three hundred. [Mid-1700s]


Reduce the price of, as in They knocked it down by another hundred dollars, or An overabundant harvest will knock down corn prices. [Colloquial; mid-1800].


Earn as wages, as in She knocks down a hundred grand a year. [Slang; 1920s]


Steal, embezzle, as in He was caught knocking down the box-office receipts. This usage may be obsolescent. [Slang; mid-1800s] Also see knock over, def. 2.


In addition to the idioms beginning with knock

  • knock about
  • knock back
  • knock cold
  • knock dead
  • knock down
  • knock down with a feather
  • knock for a loop
  • knock into a cocked hat
  • knock it off
  • knock off
  • knock oneself out
  • knock on wood
  • knock out
  • knock over
  • knock over with a feather
  • knock someone's block off
  • knock someone's socks off
  • knock the bottom out of
  • knock the living daylights out of
  • knock the socks off
  • knock together
  • knock up

also see:

  • beat (knock) into someone's head
  • beat (knock) the living daylights out of
  • (knock) down to size
  • (knock) off someone's feet
  • school of hard knocks
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.