'knocker' definitions:

Definition of 'knocker'

From: WordNet
noun
(Yiddish) a big shot who knows it and acts that way; a boastful immoderate person
noun
A person who knocks (as seeking to gain admittance); "open the door and see who the knocker is"
noun
One who disparages or belittles the worth of something [syn: detractor, disparager, depreciator, knocker]
noun
Either of two soft fleshy milk-secreting glandular organs on the chest of a woman [syn: breast, bosom, knocker, boob, tit, titty]
noun
A device (usually metal and ornamental) attached by a hinge to a door [syn: knocker, doorknocker, rapper]

Definition of 'knocker'

From: GCIDE
  • knocker \knock"er\, n.
  • 1. One who, or that which, knocks; specifically, an instrument, or kind of hammer, fastened to a door, to be used in seeking for admittance. [1913 Webster]
  • Shut, shut the door, good John ! fatigued, I said; Tie up the knocker; say I'm sick, I'm dead. --Pope. [1913 Webster]
  • 2. A person strikingly handsome, beautiful, or fine; one who wins admiration; a "stunner." [Slang.] [Webster 1913 Suppl.]
  • 3. A species of large cockroach, especially {Blabera gigantea}, of semitropical America, which is able to produce a loud knocking sound. [Webster 1913 Suppl.]
  • 4. [usually used in pl.] a woman's breast. [vulgar] [PJC]

Synonyms of 'knocker'

From: Moby Thesaurus