KNOCKER
knocker, doorknocker, rapper
(noun) a device (usually metal and ornamental) attached by a hinge to a door
breast, bosom, knocker, boob, tit, titty
(noun) either of two soft fleshy milk-secreting glandular organs on the chest of a woman
detractor, disparager, depreciator, knocker
(noun) one who disparages or belittles the worth of something
knocker
(noun) a person who knocks (as seeking to gain admittance); “open the door and see who the knocker is”
knocker
(noun) (Yiddish) a big shot who knows it and acts that way; a boastful immoderate person
Source: WordNet® 3.1
Etymology
Noun
knocker (plural knockers)
A device, usually hinged with a striking plate, used for knocking on a door.
A person who knocks.
A critic; one who disparages.
(informal, derogatory) A person who knocks (denigrates) something.
(slang, usually, in the plural) A woman's breasts.
(especially Cardigan, in South Wales, archaic) A dwarf, goblin, or sprite imagined to dwell in mines and to indicate the presence of ore by knocking. [18th to 19th c.]
(pinball) A mechanical device in a pinball table that produces a loud percussive noise.
(dated, slang) A person who is strikingly handsome or otherwise admirable; a stunner.
A large cockroach, especially Blaberus giganteus, of semitropical America, which is able to produce a loud knocking sound.
(geology) A large, boulder-shaped outcrop of bedrock in an otherwise low-lying landscape, chiefly associated with a mélange.
(slang) One who defaults on payment of a wager.
Synonyms
• (a woman's breasts): See also breasts
Source: Wiktionary
Knock"er, n.
Definition: One who, or that which, knocks; specifically, an instrument, or
kind of hammer, fastened to a door, to be used in seeking for
admittance.
Shut, shut the door, good John ! fatigued, knocker; say I'm sick, I'm
dead. Pope.
Source: Webster’s Unabridged Dictionary 1913 Edition