v. & n.
—n. the harsh sound made by ducks.
—v.intr.
1 utter this sound.
2 colloq. talk loudly and foolishly.
Etymology: imit.: cf. Du. kwakken, G quacken croak, quack
2.
n.
1 a an unqualified practiser of medicine. b (attrib.) of or characteristic of unskilled medical practice ({{}}quack cure).
2 a charlatan.
3 sl. any doctor or medical officer.
Derivatives:
quackery n. quackish adj.
Etymology: abbr. of quacksalver f. Du. (prob. f. obs. quacken prattle + salf SALVE(1))
Useful english dictionary. 2012.