• WordNet 3.6
    • adj quack medically unqualified "a quack doctor"
    • v quack act as a medical quack or a charlatan
    • v quack utter quacking noises "The ducks quacked"
    • n quack the harsh sound of a duck
    • n quack an untrained person who pretends to be a physician and who dispenses medical advice
    • ***
Webster's Revised Unabridged Dictionary
  • Interesting fact: A duck's quack doesn't echo, and no one knows why.
    • Quack A boastful pretender to medical skill; an empiric; an ignorant practitioner.
    • Quack Hence, one who boastfully pretends to skill or knowledge of any kind not possessed; a charlatan. "Quacks political; quacks scientific, academical."
    • a Quack Pertaining to or characterized by, boasting and pretension; used by quacks; pretending to cure diseases; as, a quack medicine; a quack doctor.
    • Quack The cry of the duck, or a sound in imitation of it; a hoarse, quacking noise.
    • Quack To act the part of a quack, or pretender.
    • Quack To make vain and loud pretensions; to boast. "To quack of universal cures."
    • Quack To utter a sound like the cry of a duck.
    • ***
Century Dictionary and Cyclopedia
  • Interesting fact: Recent scientific research has has shown Duck's quacks DO echo, even though they are commonly thought not to because the echo is can not be heard by the human ear.
    • quack To utter a harsh, flat, croaking sound or cry, as a goose or duck; croak; now, usually, to cry as a duck.
    • quack To make an outcry: said of persons.
    • n quack A harsh, croaking sound.
    • n quack The cry of a duck; a quacking.
    • quack To talk noisily and ostentatiously; make vain and loud pretensions.
    • quack To play the quack; practise arts of quackery, as a pretender to medical skill.
    • quack To treat in the manner of a quack; play the quack with.
    • quack To tamper with dishonestly; use fraudulently.
    • n quack An impudent and fraudulent pretender to medical skill; a mountebank; a knavish practitioner of medicine.
    • n quack Hence One who pretends to skill or knowledge of any kind which he does not possess; an ignorant and impudent pretender; a charlatan.
    • n quack Synonyms Quack, Empiric, Mountebank, Charlatan. A quack is, by derivation, one who talks much without wisdom, and, specifically, talks of his own power to heal; hence, any ignorant pretender to medical knowledge or skill. Empiric is a more elevated term for one who goes by mere experience in the trial of remedies, and is without knowledge of the medical sciences or of the clinical observations and opinions of others; hence, an incompetent, self-confident practitioner. A mountebank is generally a quack, but may be a pretender in any line. Charlatan (literally ‘chatterer’) is primarily applied, not to a person belonging to any particular profession or occupation, but to a pretentious cheat of any sort.
    • quack Pertaining to or characterized by quackery of any kind; specifically, falsely pretending to cure disease, or ignorantly or fraudulently set forth as remedies: as, a quack doctor; quack medicines.
    • n quack See couac.
    • ***
Chambers's Twentieth Century Dictionary
    • v.i Quack kwak to cry like a duck: to boast: to practise as a quack
    • v.t Quack to doctor by quackery
    • n Quack the cry of a duck: a boastful pretender to skill which he does not possess, esp. medical skill: a mountebank
    • adj Quack pertaining to quackery: used by quacks
    • ***


  • Richard C. Cushing
    Richard C. Cushing
    “When I see a bird that walks like a duck and swims like a duck and quacks like a duck, I call that bird a duck.”


Webster's Revised Unabridged Dictionary
Of imitative origin; cf. D. kwaken, G. quacken, quaken, Icel. kvaka, to twitter


In literature:

Let us not live like quacks.
"The Golden Censer" by John McGovern
My friend is neither a quack nor superstitious, and two hundred years ago would have been a better physician than most in Europe.
"Letters from Egypt" by Lucie Duff Gordon
The man seemed to brook with scorn the degrading situation of a religious quack, to which some uncontrollable destiny had doomed him.
"The Haunters & The Haunted" by Various
It grows and spreads equal to quack-grass.
"Trees, Fruits and Flowers of Minnesota, 1916" by Various
They were swimming in circles, quacking and stretching their wings, evidently in great excitement.
"Ways of Wood Folk" by William J. Long
But when the quack engaged with Job I spy'd, The Lord have mercy on poor Job I cry'd.
"History of English Humour, Vol. 1 (of 2)" by Alfred Guy Kingan L'Estrange
The suppression of quack practice, drug-store prescribing, and advertising of cures for these diseases.
"The Third Great Plague" by John H. Stokes
I doctored and fussed with quack medicines for about one year and a half and found no relief.
"The People's Common Sense Medical Adviser in Plain English" by R. V. Pierce
The quacks and money-making sharks will get the upper hand.
"The Place Beyond the Winds" by Harriet T. Comstock
All I wanted to avoid was quack remedies.
"King John of Jingalo" by Laurence Housman

In poetry:

The curtain's up - the stage all black -
Time and the year nigh sped -
Time as an advertising quack -
The Old Year nearly dead.
"At a Pantomime." by William Schwenck Gilbert
Be thou real also, be no sham or quack,
Half seen as manhood sickens and expires,
Two beings in thee resting back to back,
And turning vane-like as the world desires.
"Carlyle" by Alexander Anderson
I sing of a doctor—a doctor I sing;
God send such a doctor to every bad king;
For this is a quack of superlative skill,—
If he cannot cure, he can certainly kill.
"Lines On A Quack Doctor" by Samuel Bamford
"Do you know," said the turkey, "you're quacking!
There's a fox creeping up thro' the rye;
And, if you're not utterly lacking,
You'll make for that duck-pond. Good-bye!"
"The New Duckling" by Alfred Noyes
You came and quacked beside me in the wood.
You said, "The view from here is very good!"
You said, "It's nice to be alone a bit!"
And, "How the days are drawing out!" you said.
You said, "The sunset's pretty, isn't it?"
"The Voice" by Rupert Brooke
On that deep soil great Rome was sown;
Our England her foundations laid:--
Hence, while the nations, change-dismay'd,
To tyrant or to quack repair,
A healthier heart we own,
And the plant Man grows stronger than elsewhere.
"A Dorset Idyl" by Francis Turner Palgrave

In news:

NEWARK — A celebration of the life of Richard "Dick" Quack will be held Monday at 11 am at the Heath Church of Christ, 1331 Chapel Way, with Pastor Ray Linn presiding.
Only Simon Baker Would Make Us Watch a Telepathic Quack .
It is this sense of community in taking responsibility for our co-existing wildlife that has made Doctor Quack 's Wildlife Volunteer Program so successful.
ButSmith said that according to his `` Quack Log, Homer has onlyaveraged 7-point-8 quacks a day since May.
A judge said he wasn't convinced the quacking was continuous andloud enough to constitute an unreasonable noise.
You'll surely quack a smile.
If it looks like a duck and quacks like a duck, could it be a duck.
The first Masterworks concert of the season for the Memphis Symphony Orchestra stepped off to a quacking good start Saturday night.
Quack decides that a baby duck would make his pond even more perfect.
"It's not a pipeline," DC Assault president Curtis Malone says, even though it sure waddles and quacks like one these days.
A person gets the impression from quack health advertising that millions among us believe not only in the tooth fairy but also in hunger-free diets .
" Duck Dynasty" is nothing to quack at.
"Duck Dynasty " is nothing to quack at.
But for some reason I can't change the channel whenever these ZZ-Top looking quacks are on.
Yes, both campaigns then ran smack into the quack attack.

In science:

Third is a new class of radio transients, which at least look and quack like ducks (sorry, pulsars), though we are not quite sure about the walking as no proper motions were reported.
Astrophysics in 2006
It is not known whether all C ∗ -algebras that look like Cuntz-Krieger algebras (and quack like Cuntz-Krieger algebras) are Cuntz-Krieger algebras.
Do phantom Cuntz-Krieger algebras exist?