KNOCK

I. verb Etymology: Middle English knoken, from Old English cnocian; akin to Middle High German knochen to press Date: before 12th century intransitive verb to strike something with a sharp blow, to collide with something, 3. bustle , wander , 4. to make a pounding noise, to have engine ~, to find fault, transitive verb 1. a. to strike sharply, to drive, force, or make by or as if by so striking , to set forcibly in motion with a blow, to cause to collide, to find fault with , II. noun Date: 14th century 1. a sharp blow ; rap , hit , b. a severe misfortune or hardship, setback , reversal , 2. a pounding noise, a sharp repetitive metallic noise caused by abnormal ignition in an automobile engine, a harsh and often petty criticism