quack

Noun (1)

quack (plural quacks)

1. The vocalisation made by a duck.
   • Did you hear that duck make a quack?
   • Twice a day she took them out to feed in the marshy places, let them waddle and gobble for an hour or two, and then drove them back and shut them up in a small dark shed to digest their meal, whence they gave forth occasionally a melancholy quack.1869, Alfred Russel Wallace, The Malay Archipelago, volume 1, London: Macmillan and Co., page 356

Verb (1)

quack (third-person singular simple present quacks, present participle quacking, simple past and past participle quacked)

1. Of a duck, to make its characteristic vocalisation.
   • The more breadcrumbs I threw on the ground, the more they quacked.
   • Do you hear the ducks quack?
2. To make a sound similar to the quack of a duck.
3. (intransitive) Of a queen bee: to make a high-pitched sound during certain stages of development.

Interjection

1. A duck's quack.

Noun (2)

quack (plural quacks)

1. (derogatory) A fraudulent healer, especially a bombastic peddler in worthless treatments, a doctor who makes false diagnoses for monetary benefit, or an untrained or poorly trained doctor who uses fraudulent credentials to attract patients
   • That doctor is nothing but a lousy quack!
   • Tis hard to say, how much these Arse-wormes do urge us, We now need no Quack but these Jacks for to purge us, …1662, Rump: or an Exact Collection of the Choycest Poems and Songs Relating to Late Times, Vol. II, by ‘the most Eminent Wits’
2. (derogatory, figuratively) Any similar charlatan or incompetent professional.
   • The very quaik of faſhions, the very hee that / VVeares a Steletto on his chinne.c. 1635–1636 (date written), Iohn Ford [i.e., John Ford], The Fancies, Chast and Noble: […], London: […] E[lizabeth] P[urslowe] for Henry Seile, […], published 1638, →OCLC, Act III, page 32
3. (derogatory, humorous, mildly, slang) Any doctor.
   • That quack wants me to quit smoking, eat less, and start exercising. The nerve!

Verb (2)

quack (third-person singular simple present quacks, present participle quacking, simple past and past participle quacked)

1. To practice or commit quackery (fraudulent medicine).
   • […] it is incredible, and scarce to be imagin’d, how the Posts of Houses, and Corners of Streets were plaster’d over with Doctors Bills, and Papers of ignorant Fellows; quacking and tampering in Physick, and inviting the People to come to them for Remedies;1722, Daniel Defoe, “A Journal of the Plague Year”, in et al., London: E. Nutt, page 36
2. (obsolete) To make vain and loud pretensions.
   • Seek out for Plants with Signatures
     To Quack of Universal Cures1684, Samuel Butler, Hudibras, London, Part 3, Canto 1, p. 18

   Synonyms:

   boast

Adjective

quack (comparative more quack or quacker, superlative most quack or quackest)

1. Falsely presented as having medicinal powers.
   • Don't get your hopes up; that's quack medicine!
   • In precisely the same way does a quack doctor prescribe his infallible nostrum to every patient, without taking into account differences of constitution, or [...]1833, James Rennie, “The Word Gardening”, in Alphabet of Scientific Gardening for the Use of Beginners, London: William Orr, page 2