quack Meaning, Definition & Usage

  1. noun an untrained person who pretends to be a physician and who dispenses medical advice
  2. noun the harsh sound of a duck
  3. verb utter quacking noises
    • The ducks quacked
  4. verb act as a medical quack or a charlatan
  5. adjective satellite medically unqualified
    • a quack doctor

WordNet

Quack intransitive verb
Etymology
Of imitative origin; cf. D. kwaken, G. quacken, quaken, Icel. kvaka to twitter.
Wordforms
imperfect & past participle Qvacked ; present participle & verbal noun Quacking
Definitions
  1. To utter a sound like the cry of a duck.
  2. To make vain and loud pretensions; to boast. " To quack of universal cures." Hudibras.
  3. To act the part of a quack, or pretender.
Quack noun
Definitions
  1. The cry of the duck, or a sound in imitation of it; a hoarse, quacking noise. Chaucer.
  2. Cf. Quacksalver. A boastful pretender to medical skill; an empiric; an ignorant practitioner.
  3. Hence, one who boastfully pretends to skill or knowledge of any kind not possessed; a charlatan.
    Quacks political; quacks scientific, academical. Carlyle.
Quack adjective
Definitions
  1. Pertaining to or characterized by, boasting and pretension; used by quacks; pretending to cure diseases; as, a quack medicine; a quack doctor.

Webster 1913