mountebank

"CORIOLANUS: Pray, be content:
Mother, I am going to the market-place;
Chide me no more. I'll mountebank their loves,
Cog their hearts from them, and come home belov'd
Of all the trades in Rome."
- William Shakespeare, 'The Tragedy of Coriolanus'.

Sweeney Todd: "And furthermore, "Signor", I have serviced no kings, yet I wager that I can shave a cheek with ten times more dexterity than any street mountebank."

See also mountie bank.

I have to say, that is my favorite SNL moment of all time.

Alex Trebek: That's beautiful. And finally, Sean Connery's also here let's move on to Double Jeopardy where the categories -

Sean Connery: Not so fast Trebek.

Alex Trebek: I really thought that was going to work.

Sean Connery: Well, you were wrong, you mountebank. I pose a conundrum to ya, I riddle if you will

Alex Trebek: I don't want to hear it.

Sean Connery: What's the difference between you and a mallard with a cold? One's a sick duck and I can't remember how it ends, but your mother's a whore. Laughs

charlatan

"A flamboyant deceiver; one who attracts customers with tricks or jokes"

A mountebank practices unsubstantiated medicine as an alchemist practices unsubstantiated science

I found it on P18 of William Bonner's and Addison Wiggin's "Financial Reckoning Day":

A certain level of madness is often an advantage in the business and entertainment world, but this was too extreme for that. Purging the planet of ignorance? Only a buffoon or mountebank would say such a foolish thing. Saylor was clearly one or the other--maybe both.