(noun)
a vigorous blow
the sudden knock floored him
(noun)
the act of hitting vigorously
(verb)
find fault with; express criticism of; point out real or perceived flaws
Don't knock the food--it's free
(verb)
deliver a sharp blow or push
He knocked the glass clear across the room
(verb)
knock against with force or violence
(verb)
make light, repeated taps on a surface
(noun)
the sound of knocking (as on a door or in an engine or bearing)
the knocking grew louder
(verb)
sound like a car engine that is firing too early
(noun)
negative criticism
(noun)
a bad experience
the school of hard knocks
(verb)
rap with the knuckles
knock on the door