(Yiddish) a big shot who knows it and acts that way; a boastful immoderate person
a person who knocks (as seeking to gain admittance)
"open the door and see who the knocker is"
one who disparages or belittles the worth of something
a device (usually metal and ornamental) attached by a hinge to a door
A device, usually hinged with a striking plate, used for knocking on a door.