charlatan

This term carries a strong negative connotation of deception and intellectual dishonesty. It specifically targets individuals who project an image of professional authority or specialized expertise to exploit the gullibility of others, often for financial gain.

While similar to a general liar, a charlatan specifically mimics the trappings of a profession, such as medicine or law. The word evokes the image of a traveling salesperson or a fake healer promising impossible results through secret knowledge.