from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The characteristic sound uttered by a duck.
- intransitive v. To utter the characteristic sound of a duck.
- n. An untrained person who pretends to be a physician and dispenses medical advice and treatment.
- n. A charlatan; a mountebank.
- adj. Relating to or characteristic of a quack: a quack cure.
- intransitive v. To act as a medical quack or a charlatan.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. The sound made by a duck.
- v. To make a noise like a duck.
- n. A fraudulent healer or incompetent doctor of medicine, an impostor who claims to have qualifications to practice medicine.
- n. A charlatan.
- n. A doctor.
- v. To practice, commit quackery.
- adj. falsely presented as having medicinal powers.
from the GNU version of the Collaborative International Dictionary of English
- intransitive v. To utter a sound like the cry of a duck.
- intransitive v. To make vain and loud pretensions; to boast.
- intransitive v. To act the part of a quack, or pretender.
- n. The cry of the duck, or a sound in imitation of it; a hoarse, quacking noise.
- n. A boastful pretender to medical skill; an empiric; an ignorant practitioner.
- n. Hence, one who boastfully pretends to skill or knowledge of any kind not possessed; a charlatan.
- adj. Pertaining to or characterized by, boasting and pretension; used by quacks; pretending to cure diseases
from The Century Dictionary and Cyclopedia
- To utter a harsh, flat, croaking sound or cry, as a goose or duck; croak; now, usually, to cry as a duck.
- To make an outcry: said of persons.
- n. A harsh, croaking sound.
- n. The cry of a duck; a quacking.
- To talk noisily and ostentatiously; make vain and loud pretensions.
- To play the quack; practise arts of quackery, as a pretender to medical skill.
- To treat in the manner of a quack; play the quack with.
- To tamper with dishonestly; use fraudulently.
- n. An impudent and fraudulent pretender to medical skill; a mountebank; a knavish practitioner of medicine.
- n. Hence One who pretends to skill or knowledge of any kind which he does not possess; an ignorant and impudent pretender; a charlatan.
- n. 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.
- 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. See couac.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. an untrained person who pretends to be a physician and who dispenses medical advice
- v. act as a medical quack or a charlatan
- v. utter quacking noises
- adj. medically unqualified
- n. the harsh sound of a duck
Middle English quek, of imitative origin.
Short for quacksalver.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Middle English *quacken, queken ("to croak like a frog; make a noise like a duck, goose, or quail"), from quack, qwacke, quek, queke ("quack", interjection and noun), also kek, keke, whec-, partly of imitative origin and partly from Middle Dutch quacken ("to croak, quack"), from Old Dutch *kwaken ("to croak, quack"), from Proto-Germanic *kwakanan, *kwakōnan (“to croak”), of imitative origin. Cognate with Saterland Frisian kwoakje, Middle Low German quaken ("to quack, croak"), German quaken ("to quack, croak"), Danish kvække ("to croak"), Swedish kväka ("to croak, quackle"), Norwegian kvekke ("to croak"), Icelandic kvaka ("to twitter, chirp"). (Wiktionary)