• IPA: /kwæk/

quack (plural quacks)

1. The sound#Noun|sound made by a duck#Noun|duck.

   Did you hear that duck make a quack?

• French: coin-coin
• German: Quaken
• Italian: qua qua
• Portuguese: quac
• Russian: кря-кря
• Spanish: cuac

quack (quacks, present participle quacking; past and past participle quacked)

1. To make a noise#Noun|noise like a duck#Noun|duck.

   The more breadcrumbs I threw on the ground, the more they quacked.

   Do you hear the ducks quack?

• French: cancaner
• German: quaken
• Italian: ^{(please verify)} fare#Italian|fare qua qua , anatrare
• Portuguese: grasnar, grasnir, grassitar, gracitar
• Russian: кря́кать
• Spanish: graznar, parpar

quack (plural quacks)

1. A fraudulent healer or incompetent professional; especially, a doctor#Noun|doctor of medicine who makes false diagnoses or inappropriate treatment; an impostor who claims to have qualifications to practice#Verb|practice medicine. [from c. 1630]

   That doctor is nothing but a lousy quack!

   • 1662, Rump: or an Exact Collection of the Choycest Poems and Songs Relating to Late Times, Vol. II, by ‘the most Eminent Wits’

     Tis hard to say, how much these Arse-wormes do urge us, We now need no Quack but these Jacks for to purge us, [...]

   • 1843, Thomas Carlyle, Past and Present, book 2, ch. 8, The Electon

     ‘if we are ourselves valets, there shall ‘exist no hero for us; we shall not know the hero when we see him;’ - we shall take the quack for a hero; and cry, audibly through all ballot-boxes and machinery whatsoever, Thou art he; be thou King over us!

   • 1885, W[illiam] S[chwenck] Gilbert; Arthur Sullivan, composer, “A More Humane Mikado”, in […] The Mikado; or, The Town of Titipu, London: Chappel & Co., […], OCLC 25083293 ↗, Act II, page 36 ↗:

     The advertising quack who wearies / With tales of countless cures, / His teeth, I've enacted, / Shall all be extracted / By terrified amateurs.

   • 1981, S.O.B. (film):

     Polly (to security guard, referring to Dr. Feingarten): Are you going to let that shyster in there?

     Dr. Feingarten: I could sue you, Polly. A shyster is a disreputable lawyer. I'm a quack.

2. A charlatan.
3. (slang) A doctor.

• medicaster (dated)
• quacksalver
• See also Thesaurus:deceiver

• French: charlatan, charlatane
• German: Quacksalber, Kurpfuscher
• Portuguese: mata-sanos
• Russian: шарлата́н
• Spanish: matasanos

• French: charlatan, charlatane
• German: Quacksalber, Quacksalberin
• Italian: ciarlatano, imbonitore, pataccaro
• Portuguese: charlatão
• Russian: шарлата́н
• Spanish: charlatán

• French: toubib
• Italian: mediconzolo
• Portuguese: curandeiro
• Spanish: curandero

quack (quacks, present participle quacking; past and past participle quacked)

1. To practice or commit quackery (fraudulent medicine).
   • 1722, Daniel Defoe, A Journal of the Plague Year, London: E. Nutt et al., p. 36,

     […] 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;

2. (obsolete) To make vain and loud pretensions.

   Synonyms: boast

   • 1684, Samuel Butler, Hudibras, London, Part 3, Canto 1, p. 18,

     Seek out for Plants with Signatures

     To Quack of Universal Cures

quack (quacker and quackest are rare, and probably used humorously)

1. Falsely present#Verb|presented as having medicinal power#Noun|powers.

   Don't get your hopes up; that's quack medicine!

• Italian: empirico