Words related to quack
"medicinal ointment or adhesive preparation for external use on wounds and sores," Old English sealf "healing ointment," from West Germanic *salbo- "oily substance" (source also of Old Saxon salba, Middle Dutch salve, Dutch zalf, Old High German salba, German salbe "ointment"), from PIE *solpa-, from root *selp- "fat, butter" (source also of Greek elpos "fat, oil," Albanian gjalpë "butter," Sanskrit sarpis "melted butter"). Beekes, however, sees a Pre-Greek word.
The figurative sense of "something to soothe" wounded pride, etc. is from 1736; earlier figurative use was as "a spiritual or religious remedy" (12c.).
"absurd or fabricated story intended as an imposition," 1851, perhaps 1843, from French canard "a hoax," literally "a duck" (from Old French quanart, probably echoic of a duck's quack); said by Littré to be from the phrase vendre un canard à moitié "to half-sell a duck," thus, perhaps from some long-forgotten joke, "to cheat." But also compare quack (n.1).