Quack

A pretender to medical skill; a medical charlatan

Any person with characteristic pretensions, misrepresentations, practices, and/or methods who is unqualified or incompetent in the field to which such distinctions pertain. The word “quack” traces to two Dutch words: the obsolete verb “quacken,” which meant “to chatter or prattle,” and “salf,” a relative of the English word “salve.” Old-time quacksalvers were simply persons who bragged about the medicinals they offered.