mountebank

Etymology

From archaic Italian montambanco (“quack who mounts a bench to hawk his wares”), contracted from monta-in-banco (“mount on bench”).

noun

1. One who sells dubious medicines.
   A personage appears before him with a broad-brimmed hat, such as the students wear at Wittenberg, a wandering clerk, perhaps, or a charlatan Juggler, a mountebank at a fair, who has laid out on a stand a laboratory of ill-assorted jars. 1976 [1969], chapter 6, in William Weaver, transl., The Castle of Crossed Destinies, translation of Il castello dei destini incrociati by Italo Calvino, part 2, page 92
2. One who sells by deception; a con artist.
   Are you allowing yourselves to be fooled by this mountebank, this harlequin? Do you cringe before a religion compounded of clouds and moonbeams? This man is an imposter and the Galactic Spirit he speaks of a fraud of the imagination devised to—— 1951, Isaac Asimov, Foundation (1974 Panther Books Ltd publication), part III: “The Mayors”, chapter 7, page 106, ¶ 13
   Gary Dahl, the man behind that scheme—described variously as a marketing genius and a genial mountebank—died on March 23 at 78. 2015-03-31, Margalit Fox, “Gary Dahl, Inventor of the Pet Rock, Dies at 78”, in The New York Times, →ISSN
3. Any boastful, false pretender.
4. (obsolete) An acrobat.

verb

1. (intransitive) To act as a mountebank.
2. (transitive) To cheat by boasting and false pretenses.