There are 2 main definitions of quack in English:

quack1

Line breaks: quack
Pronunciation: /kwak
 
/

noun

The characteristic harsh sound made by a duck: I heard a quack and saw some ducks huddled together
More example sentences
  • But even from the vague hints he throws out, I think we may rest assured it will not be the last quack of a lame duck.
  • This is an interesting link for anyone who was wondering about those duck quacks.
  • I'm sorry to say that it's not true about the quack of a duck.

verb

[no object] Back to top  
1(Of a duck) make a quack: ducks quacked from the lake
More example sentences
  • Yet, in case after case, the chicken always ended up dead, while the duck went happily quacking down the river.
  • We strolled up a steep street, where wild ducks quacked for food outside a shop, and into a quiet garden.
  • Down near the pond, the ducks were quacking at an old couple that was throwing pieces of stale bread at them.
1.1 informal (Of a person) talk loudly and foolishly: he was still quacking about vinyl’s alleged superiority to CDs
More example sentences
  • Ever since Ride the Ducks came to town, I've watched those vessels drive by, its frenzied tourists quacking away.
  • Some of these remedies have been closer to quack concoctions.

Origin

mid 16th century (as a verb): imitative.

Definition of quack in:

Get more from Oxford Dictionaries

Subscribe to remove ads and access premium resources

There are 2 main definitions of quack in English:

quack2

Line breaks: quack
Pronunciation: /kwak
 
/

noun

1A person who dishonestly claims to have special knowledge and skill in some field, typically medicine: [as modifier]: a quack doctor quack cures
More example sentences
  • As with most quack cure claims about ‘toxins’, the actual toxins were not named.
  • An alternative medicine quack reckoned he could cure Faulkner of his twitching with a six-month course of treatment.
  • But why wouldn't they believe the claims of the detox quacks?
Synonyms
British informal twister
North American informal grifter, bunco artist, chiseller
Australian informal shicer, magsman, illywhacker
1.1British informal A doctor: he went to see the quack this morning
More example sentences
  • In India, this could range from private practitioners, to hospitals, nursing homes, polyclinics, alternative medical practitioners, quacks and pharmacists.
Synonyms
doctor, physician, medical practitioner, medical man/woman/person;
Navy surgeon
informal doc, medic, medico
archaic leech, sawbones

Origin

mid 17th century: abbreviation of earlier quacksalver, from Dutch, probably from obsolete quacken 'prattle' + salf, zalf (see salve1).

Derivatives

quackery

noun
More example sentences
  • The Skeptic's Dictionary is a compendium of detailed information about oft-repeated hoaxes, legends and quackery.
  • Why did this quackery get so far before being exposed?
  • Alarm made him listen to all manner of quackery.

quackish

adjective
More example sentences
  • Barrett goes on to describe the history of naturopathy and to list some of the quackish practices that have been included in naturopathy.
  • Obviously, Paul, anyone stupid enough to take your quackish advice deserves their outcomes.

Definition of quack in: