knock definition

1. the sound of knocking (as on a door or in an engine or bearing)
• examples: the knocking grew louder
2. negative criticism
3. a vigorous blow
• examples: the sudden knock floored him
• examples: he took a bash right in his face
• examples: he got a bang on the head
4. a bad experience
• examples: the school of hard knocks
5. the act of hitting vigorously
• examples: he gave the table a whack
6. deliver a sharp blow or push :
• examples: He knocked the glass clear across the room
7. rap with the knuckles
• examples: knock on the door
8. find fault with; express criticism of; point out real or perceived flaws
• examples: The paper criticized the new movie
• examples: Don't knock the food--it's free