Noun
1. (Yiddish) a big shot who knows it and acts that way; a boastful immoderate person
2. a person who knocks (as seeking to gain admittance);
"open the door and see who the knocker is"3. one who disparages or belittles the worth of something
4. either of two soft fleshy milk-secreting glandular organs on the chest of a woman
5. a device (usually metal and ornamental) attached by a hinge to a door