quacksalver KWAK-sal-ver, noun:
1. a charlatan.
2. a quack doctor.

And there was that quacksalver Mellowes again, with his pernicious theory that consumption was caused by an excess of oxygen.
— Patrick O’Brian, Desolation Island, 1978

Anon, we grow persuaded that he traded both eyes for hooks and beneath the roof of his friend, Prince of Hesse Cassel, this Quacksalver expired to the winding from a strange horn one overcast night at Sleswig — and doubt not that at the bar he lifted up both hands to please innocent!
— Evan S. Connell, The Alchymist’s Journal, 1991

Even more outlandish than she is, he thought. “We shall not have her degraded as some quacksalver’s drab.
— Ariana Franklin, Mistress of the Art of Death, 2007

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Quacksalver comes from an early Dutch word of the same spelling referring to someone who prescribes home remedies. It is the root of the more common word quack.