an untrained person who pretends to be a physician and who dispenses medical advice
the harsh sound of a duck
The sound made by a duck.
A fraudulent healer or incompetent professional; especially, a doctor of medicine who makes false diagnoses or inappropriate treatment; an impostor who claims to have qualifications to practice medicine.
Falsely presented as having medicinal powers.
The word "quack" comes from Middle English and originally meant to make the noise of a frog or duck. It is an onomatopoeic term derived from Old Dutch and Proto-Germanic roots that imitated these animal sounds.