[ kwak ]
See synonyms for quack on Thesaurus.com
  1. the harsh, throaty cry of a duck or any similar sound.

verb (used without object)
  1. to utter the cry of a duck or a sound resembling it.

Origin of quack

First recorded in 1570–80; imitative; compare Dutch kwakken, German quacken

Other definitions for quack (2 of 2)

[ kwak ]

  1. a fraudulent or ignorant pretender to medical skill: Desperation for a cure led her to a quack who took her money.

  2. a person who pretends, professionally or publicly, to have skill, knowledge, or qualifications they do not possess; a charlatan.

  1. being a fraudulent or ignorant pretender to skills, especially medical skills: He's just a quack psychologist who complicates everyone's problems.

  2. presented falsely as having curative powers: quack medicine.

  1. of, relating to, or befitting a quack or quackery: Her quack methods have helped no one.

verb (used with object)
  1. to treat in the manner of a fraudulent or ignorant pretender to medical skill.

  2. to advertise or sell with fraudulent claims.

Origin of quack

First recorded in 1630–40; short for quacksalver

Other words for quack

Other words from quack

  • quack·ish, adjective
  • quack·ish·ly, adverb
  • quack·ish·ness, noun

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use quack in a sentence

  • "Better than grubbing for bugs in the dirty earth, this nice clean cool water," quacked he, and he was as happy as happy could be.

    Seven O'Clock Stories | Robert Gordon Anderson
  • The greedy duck snatched it, and in less than half a minute she opened her great bill again, and quacked for more.

  • They quacked and scuffled in the thick reeds at night, as we walked near them.

  • The Duck quacked and made a great noise, but she was soon silenced.

    Canadian Fairy Tales | Cyrus Macmillan
  • The duck flew in, as before, and the prince caught her by the wing; she quacked, and tried to get away.

    Polish Fairy Tales | A. J. Glinski

British Dictionary definitions for quack (1 of 2)


/ (kwæk) /

  1. (of a duck) to utter a harsh guttural sound

  2. to make a noise like a duck

  1. the harsh guttural sound made by a duck

Origin of quack

C17: of imitative origin; related to Dutch kwakken, German quacken

British Dictionary definitions for quack (2 of 2)


/ (kwæk) /

    • an unqualified person who claims medical knowledge or other skills

    • (as modifier): a quack doctor

  1. British, Australian and NZ informal a doctor; physician or surgeon

  1. (intr) to act in the manner of a quack

Origin of quack

C17: short for quacksalver

Derived forms of quack

  • quackish, adjective

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012