(Noun) A charlatan, a person who falsely claims knowledge of or skill in some matter, especially for personal gain; a person who pretends to be something he or she is not, in order to gain prestige, fame, etc.

In Context

“Whether patriot or scoundrel, military mountebank or tactical genius, epic hero or unwelcome ghost of a repressive society best forgotten, he remains what he always was: a fascinating story and a fascinating storyteller who must be approached obliquely, stalked with the same guerrilla tactics that he made famous during the Civil War.”

Paul Ashdown and Edward Caudill, The Mosby Myth: A Confederate Hero in Life and Legend, 2002.