An Etymological Dictionary of the German Language/Annotated/Quacksalber

by Friedrich Kluge

Quacksalber, masculine, ‘quack’; Modern High German only; originally a Low German word; corresponding to English quack, Dutch kwakzalver, a compound of zalf, ‘salve’ (compare Old High German salbâni, ‘seller of ointment, physician’). The first part of the compound seems to come from the verb quaken (which see), ‘to boast’; hence Quacksalber, ‘boasting physician’?.