What is Charlatan?

Legal Definition
A charlatan (also called swindler or mountebank) is a person practising quackery or some similar confidence trick in order to obtain money, fame or other advantages via some form of pretense or deception.

The word comes from French charlatan, a seller of medicines who might advertise his presence with music and an outdoor stage show. The best known of the Parisian charlatans was Tabarin, who set up a stage in the Place Dauphine, Paris in 1618, and whose commedia dell'arte inspired skits and farces inspired Molière. The word can also be traced to Spanish; charlatán, an indiscreetly talkative person, a chatterbox. Ultimately, etymologists trace "charlatan" from either the Italian ciarlare, to chatter or prattle; or from Cerretano, a resident of Cerreto, a village in Umbria, known for its quacks.
-- Wikipedia
Legal Definition
A cheat or impostor.
-- Ballentine's Law Dictionary