Dictionary definition · knock
noun
- the sound of knocking (as on a door or in an engine or bearing)"the knocking grew louder"
- negative criticism
- a vigorous blow"the sudden knock floored him"
- a bad experience"the school of hard knocks"
- the act of hitting vigorously"he gave the table a whack"
verb
- deliver a sharp blow or push"He knocked the glass clear across the room"
- rap with the knuckles"knock on the door"
- knock against with force or violence"My car bumped into the tree"
- make light, repeated taps on a surface"he was tapping his fingers on the table impatiently"
- sound like a car engine that is firing too early"the car pinged when I put in low-octane gasoline"
- find fault with; express criticism of; point out real or perceived flaws"The paper criticized the new movie"
Source: Open English WordNet (CC BY 4.0).