Religion and philosophy have been impudent and quackish—quackish!
quackish absurdities of so glaring a nature have, however, long been scorned in civilized society.
And yet to the quackish lecturer it is the key to unlock all his scientific treasures.
Finally, we love De Quincey for his abhorrence of all knavish or quackish men, and his deep respect for human nature.
"to make a duck sound," 1610s, earlier quake (1520s), variant of quelke (early 14c.), of echoic origin (cf. Middle Dutch quacken, Old Church Slavonic kvakati, Latin coaxare "to croak," Greek koax "the croaking of frogs," Hittite akuwakuwash "frog"). Middle English on the quakke (14c.) meant "hoarse, croaking." Related: Quacked; quacking.
"medical charlatan," 1630s, short for quacksalver (1570s), from obsolete Dutch quacksalver (modern kwakzalver), literally "hawker of salve," from Middle Dutch quacken "to brag, boast," literally "to croak" (see quack (v.)) + salf "salve," salven "to rub with ointment" (see salve (v.)). As an adjective from 1650s. The oldest attested form of the word in this sense in English is as a verb, "to play the quack" (1620s). The Dutch word also is the source of German Quacksalber, Danish kvaksalver, Swedish kvacksalvare.
duck sound, 1839, from quack (v.).
An untrained person who pretends to be a physician and dispenses medical advice and treatment.
An incompetent and fraudulent doctor
[1659+; a shortening of quacksalver, ''a person who boasts about the virtues of his worthless remedies''; fr Dutch and found by 1579]