Impostor, n.
Etymology: [L. impostor a deceiver, fr. imponere to impose upon, deceive. See Impone.]
One who imposes upon others; a person who assumes a character or title not his own, for the purpose of deception; a pretender. "The fraudulent impostor foul." Milton.
Syn. -- Deceiver; cheat; rogue. See Deceiver.
Shades of meaning
Fernald has no entry of its own for impostor; he lists it under hypocrite.
Where he writes about it:
The cheat and impostor endeavor to make something out of those they may deceive. — from hypocrite
The cheat is the inferior and more mercenary, as the thimble-rig gambler; the impostor may aspire to a fortune or a throne. — from hypocrite
Antonyms
none given