knock
Americanverb (used without object)
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knocks,
present (3rd person singular)
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knocked,
past participle, past
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knocking
present participle
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to strike a sounding blow with the fist, knuckles, or anything hard, especially on a door, window, or the like, as in seeking admittance, calling attention, or giving a signal.
to knock on the door before entering.
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to strike in collision; bump.
He knocked into a table.
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to make a pounding noise.
The engine of our car is knocking badly.
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Informal. to engage in trivial or carping criticism; find fault.
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Cards. to end a game, as in gin rummy, by laying down a hand in which those cards not included in sets total less than a specific amount.
verb (used with object)
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knocks,
present (3rd person singular)
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knocked,
past participle, past
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knocking
present participle
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to give a sounding or forcible blow to; hit; strike; beat.
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to drive, force, or render by a blow or blows.
to knock a man senseless.
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to make by striking a blow or blows.
to knock a hole in the wall.
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to strike (a thing) against something else.
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Informal. to criticize, especially in a carping manner.
He's always knocking everything.
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British Slang. to astound; impress greatly.
noun
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knocks
plural
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an act or instance of knocking.
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the sound of knocking, especially a rap, as at a door.
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a blow or thump.
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Informal. an adverse criticism.
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the noise resulting from faulty combustion or from incorrect functioning of some part of an internal-combustion engine.
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Cricket. an innings.
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British Slang.
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one of a combination of dealers who bid together, rather than against each other, at an auction, and later resell the purchases among themselves.
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an auction at which this is done.
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the sale of merchandise recently obtained by a dealer at an auction.
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verb phrase
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knock up
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Slang. to make pregnant.
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to exhaust; weary; tire.
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to damage; mar.
The children knocked up the new table.
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to injure; wound.
He was afraid to come home from school all knocked up again.
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British. to wake up; rouse; call.
He knocked us up before dawn.
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knock together to make or construct in a hurry or with little attention to detail.
He knocked together a couple of tables.
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knock around / about
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to wander aimlessly or idly; loaf.
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to mistreat (someone), especially physically.
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to jar; shake up.
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knock off
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Informal. to cease activity, especially work.
to knock off at five every day.
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to stop doing something; quit.
Knock it off or you'll get into a mess.
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Slang. to dispose of; finish.
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Slang. to murder; kill.
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Slang. to die.
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Slang. to get rid of; reduce.
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Slang. to disable or defeat.
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Slang. to commit a robbery at; steal from.
The gang knocked off a gas station.
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Nautical Slang. to blow the head (of a sailing vessel) off the wind.
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to imitate, copy, or plagiarize.
to knock off designer dresses in cheap materials.
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knock back to drink (a beverage), especially quickly and heartily.
He knocked back two shots of vodka.
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knock out
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to defeat (an opponent) in a boxing match by striking such a blow that the opponent is unable to rise within the specified time.
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to render (a person) unconscious.
Those sleeping pills knocked me out for ten hours.
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to make tired or exhausted.
Christmas shopping always knocks me out.
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Informal. to produce quickly, hurriedly, or with ease.
He knocks out two poems a day.
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to damage or destroy.
The explosion knocked out the power for several hours.
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knock over
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to strike (someone or something) from an erect to a prone position.
to knock over a lamp.
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to distress; overcome.
When the announcement came we were completely knocked over.
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Slang. to rob, burglarize, or hijack.
He knocked over five banks.
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knock down
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to sell at auction by a blow of the hammer or to a bidder.
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to take apart or disassemble, as for facility in handling, storing, shipping, etc.
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Slang. to receive, as a salary or a scholastic grade; earn.
He knocks down 30 grand a year.
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Informal. to lower the price of; reduce.
to knock down end-of-season leftovers.
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Slang. to embezzle or steal (money).
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to cause (a sailing vessel) to heel, as by a gust of wind, to such a degree that it cannot right itself.
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idioms
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knock out of the box, to cause a pitcher to be removed from the box because the pitcher has permitted too many hits to be made. Also knock out.
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knock the / one's socks off, to have an overwhelming effect on.
The song knocked the socks off the audience.
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have it knocked, to be assured of success.
With a government job, he thought he had it knocked.
verb
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(tr) to give a blow or push to; strike
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(intr) to rap sharply with the knuckles, a hard object, etc, esp to capture attention
to knock at the door
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(tr) to make or force by striking
to knock a hole in the wall
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to collide (with)
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(tr) to bring into a certain condition by hitting or pushing
to knock someone unconscious
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informal (tr) to criticize adversely; belittle
to knock someone's work
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Also: pink. (intr) (of an internal-combustion engine) to emit a characteristic metallic noise as a result of faulty combustion
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(intr) (of a bearing, esp one in an engine) to emit a regular characteristic sound as a result of wear
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slang to have sexual intercourse with (a person)
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informal to hit a person with a very heavy blow
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to have a violent or unpleasant encounter with (adverse facts or circumstances)
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to daze or kill (a person) by striking on the head
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effectively to prevent the further development of (a plan)
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noun
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a blow, push, or rap
he gave the table a knock
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the sound so caused
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the sound of knocking in an engine or bearing
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informal a misfortune, rebuff, or setback
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informal unfavourable criticism
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informal (in cricket) an innings or a spell of batting
Usage
What is a basic definition of knock? Knock is a verb that means to hit something by bumping into it. Knock also means to repeatedly strike something to make a noise. Knock is used as a noun to mean a sound made by repeated tapping. Knock has many other senses as a verb and a noun. It is also used in several idioms. Knock means to strike something by bumping into it or colliding with it. This sense of knock is often followed by what was bumped into (knocked onto the floor).
- Real-life examples: In bowling, the goal is to knock down all of the pins with a bowling ball. In boxing, the competitors repeatedly knock each other in the head and body with their fists. It is difficult to build a house of cards without accidentally knocking it over.
- Used in a sentence: Shawna wasn’t paying attention and accidentally knocked over a stack of boxes.
- Used in a sentence: He knocked on the wall with his umbrella to get everyone’s attention.
- Used in a sentence: I think you have a visitor because I heard a knock at the door.
Synonym Usage
See strike.
Other Word Forms
Derived Forms
Inflected Forms
Nouns
Participles
Conjugated Forms
Present
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knocksimple
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knockssimple
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have knockedperfect
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has knockedperfect
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am knockingprogressive
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are knockingprogressive
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is knockingprogressive
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have been knockingperfect progressive
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has been knockingperfect progressive
Past
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knockedsimple
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had knockedperfect
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was knockingprogressive
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were knockingprogressive
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had been knockingperfect progressive
Future
Etymology
Origin of knock
First recorded before 1000; 1890–95 knock for def. 4; Middle English knokken, knoken (verb), Old English cnocian, cnucian; cognate with Old Norse knoka “to thump, knock”
Explanation
When you knock, you bump or strike someone or something. When you hear a knock at the door, someone on the other side is thumping it with their knuckles. You can accidentally knock your grandmother's special glass bowl off the table, and you can also knock softly on her door — or tap with your knuckles — before you go in and tell her how sorry you are. If a car engine knocks, it makes a rattling or rapping sound. Colloquially, to knock something is to reject or criticize it, and if you do, you may hear the phrase, "Don't knock it until you try it!"
Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
“If you knock out a few sets of pull-ups or biceps curls, you see your muscles popping in a way that is much harder to achieve if you squat.”
From The Wall Street Journal ● Oct. 2, 2026
“In the Palisades, this measure would have let us respond quicker, knock it down faster, protect more homes ... We would have saved more homes if we had had more firefighters, period,” he said.
From Los Angeles Times ● Oct. 1, 2026
Still, that could be a knock against the stock at a time when Micron investors are wondering just how high gross margins can go.
From MarketWatch ● Oct. 1, 2026
These weather impacts can have significant knock on effects for on crop yields, food security and economies around the globe.
From BBC ● Sep. 22, 2026
Nearing the eight o’clock hour, as the watery winter sun rose high above the creaking canopy of Deadwood, Gingersnipes was awakened by a knock.
From "The Undead Fox of Deadwood Forest" by Aubrey Hartman
He’s experienced plenty of hard knocks since being disfigured in battle by his power-hungry brother, via Vhagar’s dragon fire.
From Los Angeles Times ● Aug. 10, 2026
Like Lawrence, he has performed well in the County Championship, scoring 510 runs at 56.66, including five 50+ knocks, for Surrey, but will not automatically slot back into the side in Bethell's absence.
From BBC ● Aug. 6, 2026
"When someone knocks on your door and tells you: 'Get up, come on, leave here. This is real, you have to go.'"
From Barron's ● Jul. 11, 2026
"So, when someone rattles you, knocks you off your game, breaks your focus, you find yourself interrupted, paused, with changing disrupting rhythms."
From BBC ● Jul. 10, 2026
Mom knocks an egg against the kitchen counter.
From "I Can Make This Promise" by Christine Day
Last year, similar attacks knocked out power and heating for days on end as temperatures plummeted to -20C.
From Barron's ● Oct. 4, 2026
The 31-year-old will face compatriot James Wade in the last four after he knocked out third seed Gian van Veen with a 3-0 win.
From BBC ● Oct. 2, 2026
To address this question, we looked at a simple 1% annual fee on wealth—and it knocked the probability of making it to 95 with money remaining to 61.3%.
From The Wall Street Journal ● Sep. 30, 2026
Then I knocked another $350 off the tab by cashing in 35,000 American Express points.
From The Wall Street Journal ● Sep. 30, 2026
One night, his papers and pencils were knocked to the parlor floor by Estelle’s unearthly white gown which grew more solid, more real with each session.
From "American Spirits" by Barb Rosenstock
While Brooks canvassed for the state’s largest progressive community action organization, she thought about one of her first interactions knocking doors this cycle.
From Salon ● Oct. 2, 2026
A powerful autumnal storm lashed the heavily populated US Northeast corridor on Sunday with wind, rain and large waves, knocking out power for thousands and killing at least one person.
From Barron's ● Sep. 27, 2026
The street was cordoned off by police and fire officers could be seen knocking on the doors of neighbouring homes.
From BBC ● Sep. 22, 2026
Lockheed has spent the past year rushing to assemble new suppliers for its Patriot interceptor, a high-end missile capable of knocking down a range of airborne attacks.
From The Wall Street Journal ● Sep. 17, 2026
The ground shook harder, knocking him down to his knees.
From "I Survived the Great Alaska Earthquake, 1964" by Lauren Tarshis
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
