knocker

A device (usually metal and ornamental) attached by a hinge to a door.

Either of two soft fleshy milk-secreting glandular organs on the chest of a woman.

One who disparages or belittles the worth of something.

A person who knocks (as seeking to gain admittance).

“open the door and see who the knocker is”

(Yiddish) a big shot who knows it and acts that way; a boastful immoderate person.