n. - One who, or that which, knocks; specifically, an instrument, or kind of hammer, fastened to a door, to be used in seeking for admittance.
n. - A person strikingly handsome, beautiful, or fine; one who wins admiration; a "stunner."
n. - A species of large cockroach, esp. Blabera gigantea, of semitropical America, which as able to produce a loud knocking sound.