<p><strong>Verb (used without object)</strong></p><ul><li>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.</li><li>To strike in collision; bump: He knocked into a table.</li><li>To make a pounding noise: The engine of our car is knocking badly.</li><li>Informal: to engage in trivial or carping criticism; find fault.</li><li>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.</li></ul><p><strong>Verb (used with object)</strong></p><ul><li>To give a sounding or forcible blow to; hit; strike; beat.</li><li>To drive, force, or render by a blow or blows: to knock a man senseless.</li><li>To make by striking a blow or blows: to knock a hole in the wall.</li><li>To strike (a thing) against something else.</li><li>Informal: to criticize, especially in a carping manner: He's always knocking everything.</li><li>British Slang: to astound; impress greatly.</li></ul><p><strong>Noun</strong></p><ul><li>An act or instance of knocking.</li><li>The sound of knocking, especially a rap, as at a door.</li><li>A blow or thump.</li><li>Informal: an adverse criticism.</li><li>The noise resulting from faulty combustion or from incorrect functioning of some part of an internal-combustion engine.</li><li>Cricket: an innings.</li><li>British Slang: one of a combination of dealers who bid together, rather than against each other, at an auction, and later resell the purchases among themselves.</li><li>An auction at which this is done.</li><li>The sale of merchandise recently obtained by a dealer at an auction.</li></ul><p><strong>Verb phrase (Slang)</strong></p><ul><li>To make pregnant.</li><li>To exhaust; weary; tire.</li><li>To damage; mar: The children knocked up the new table.</li><li>To injure; wound: He was afraid to come home from school all knocked up again.</li><li>British: to wake up; rouse; call: He knocked us up before dawn.</li><li>To make or construct in a hurry or with little attention to detail: He knocked together a couple of tables.</li><li>Informal: to wander aimlessly or idly; loaf.</li><li>To mistreat (someone), especially physically.</li><li>To jar; shake up.</li><li>Informal: to cease activity, especially work: to knock off at five every day.</li><li>To stop doing something; quit: Knock it off or you'll get into a mess.</li><li>Slang: to dispose of; finish.</li><li>Slang: to murder; kill.</li><li>Slang: to die.</li><li>Slang: to get rid of; reduce.</li><li>Slang: to disable or defeat.</li><li>Slang: to commit a robbery at; steal from: The gang knocked off a gas station.</li><li>Nautical Slang: to blow the head (of a sailing vessel) off the wind.</li><li>To imitate, copy, or plagiarize: to knock off designer dresses in cheap materials.</li><li>Slang: to drink (a beverage), especially quickly and heartily: He knocked back two shots of vodka.</li><li>To defeat (an opponent) in a boxing match by striking such a blow that the opponent is unable to rise within the specified time.</li><li>To render (a person) unconscious: Those sleeping pills knocked me out for ten hours.</li><li>To make tired or exhausted: Christmas shopping always knocks me out.</li><li>Informal: to produce quickly, hurriedly, or with ease: He knocks out two poems a day.</li><li>To damage or destroy: The explosion knocked out the power for several hours.</li><li>Knock (def 28): to strike (someone or something) from an erect to a prone position: to knock over a lamp.</li><li>To distress; overcome: When the announcement came we were completely knocked over.</li><li>Slang: to rob, burglarize, or hijack: He knocked over five banks.</li><li>To sell at auction by a blow of the hammer or to a bidder.</li><li>To take apart or disassemble, as for facility in handling, storing, shipping, etc.</li><li>Slang: to receive, as a salary or a scholastic grade; earn: He knocks down 30 grand a year.</li><li>Informal: to lower the price of; reduce: to knock down end-of-season leftovers.</li><li>Slang: to embezzle or steal (money).</li><li>To cause (a sailing vessel) to heel, as by a gust of wind, to such a degree that it cannot right itself.</li></ul>