Wiktionary
show someone the door
vb. 1 (context idiomatic English) To escort someone to the exit of the premises; to expel someone from a room, gathering, etc. 2 (context idiomatic by extension especially of a person English) To dismiss or reject; to exclude someone who was formerly included.
Usage examples of "show someone the door".
But Peter's too polite to show someone the door when they're bothering him, so I've never dared to stay long.