Yet another word Shakespeare has given the English language.
In Shakespeare's play Twelfth Night the clown Feste invents a name, Quinapalus, in order to give weight to one of his own sayings by attributing it to a fancy sounding name.
Wit, an't be thy will, put me into good fooling!
Those wits, that think they have thee, do very oft
prove fools; and I, that am sure I lack thee, may
pass for a wise man: for what says Quinapalus?
'Better a witty fool, than a foolish wit.'
--FESTE
From this it has come to mean any false authority or apocryphal source. It is also used as a cleaver way of saying "I made this up" or "I don't know who said this". It is rarely used in any of these senses in everyday speech, but if you use it you will sound very smart (and probably confuse your listeners into submission).
See also: Ben Trovato, Alan Smithee, and Mrs. Harris.