quacksalver

puoskari puhekieltä One falsely claiming to possess medical or other skills, especially one who dispenses potions, ointments, etc. supposedly having curative powers.
1822, w:Sir Walter Scott|Sir Walter Scott, Peveril of the Peak, ch. 38:

"Your Grace does not mean Dr. Wilderhead's powder of projection?"

"Pshaw! he is a quacksalver, and mountebank, and beggar."

"I come before you, ladies and gentlemen, . . . to introduce to you what I call my Elixir Anthropos . . . ."

. . . He listened intently to the 'quack-salvers''' address, and from time to time his eyes would twinkle and his lips curve in an ironic smile.

One is reminded of a familiar figure of medieval fairs, who survived long in this country England, and perhaps still survives in remote districts—the quacksalver who hawks his infallible remedies from a wagon.