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 Molire. The word can also be traced to Spanish; charlatn, 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.
In usage, a subtle difference is drawn between the charlatan and other kinds of confidence trickster. The charlatan is usually a salesperson. He does not try to create a personal relationship with his marks, or set up an elaborate hoax using roleplaying. Rather, the person called a charlatan is being accused of resorting to quackery, pseudoscience, or some knowingly employed bogus means of impressing people in order to swindle his victims by selling them worthless nostrums and similar goods or services that will not deliver on the promises made for them. The word calls forth the image of an old-time medicine show operator, who has long since left town by the time the people who bought his "snake oil" or similarly named tonic realize that it does not perform as advertised.
In reported spiritual communications, a charlatan is a person who fakes evidence that a spirit is "making contact" with the medium and seekers. Notable people who have successfully debunked the claims of purported supernatural mediums include magician/scientific skeptic James Randi, Brazilian writer Monteiro Lobato and magician Harry Houdini.
Synonyms for "charlatan" include "mountebank", "shyster", and "quack." "Mountebank" comes from the Italian montambanco or montimbanco based on the phrase monta in banco - literally referring to the action of a seller of dubious medicines getting up on a bench to address his audience of potential customers.
"Quack" is a reference to "quackery" or the practice of dubious medicine.