Synonyms for Impostor:

n.

crook, wheeler dealer, CONMAN, liar, fixer, brown-nose, politician. mountebank, charlatan, true, quack. impostor (noun)
faker, fraud, pretender, fake, shammer, sham, pseudo, pseud, imposter, role player.
person pretending to be something else (noun)
faker, con artist, fraud, mountebank, impersonator, masquerader, charlatan, pseudo, sham, pretender, sharper, quack, fake.
pretender (noun)
impersonator, masquerader, sharper, mountebank, study at quack, quack, charlatan, con artist.

Other synonyms:

quack. fake
fake.
fraud
fraud.
mimic
masquerader.
pretender
sharper, mountebank, pretender.
quack
charlatan.
Other relevant words:
fake, con artist, brown-nose, impersonator, wheeler dealer, mountebank, liar, charlatan, true, CONMAN, masquerader, crook, fixer, politician, sharper, quack.

Usage examples for impostor

  1. Whatever that old impostor the Future may have in store for her, at any rate she is having a good time now." – The Danvers Jewels, and Sir Charles Danvers by Mary Cholmondeley
  2. You are an impostor you have assumed a dead man's name." – The Thin Red Line; and Blue Blood by Arthur Griffiths
  3. I knew that Abou Saood was a liar when he spoke against you; I knew that he was an impostor when he announced himself as the son of a sultan. – Ismailia by Samuel W. Baker