quack

:  a noise made by quacking

:  to act like a quack

1 :  charlatan 2 Religious quacks on radio and television thinking up new ways to take money from ignorant listeners and incidentally from legitimate churches. — Andrew A. Rooney

2 :  an ignorant, misinformed, or dishonest practitioner of medicine No doubt these misunderstandings and dashed hopes have driven many cancer patients and their families into the arms of quacks. — Haydn Bush

:  of, relating to, or used by quacks quack cancer cures

:  to make the cry of a duck

:  a cry made by a duck

:  a person who pretends to have medical knowledge and skill

:  relating to, being, or used by a person who pretends to have medical skill a quack doctor quack remedies

:  a pretender to medical skill :  an ignorant or dishonest practitioner

:  of, relating to, characteristic of, or being a quack scores of quack remedies for arthritis—Jane E. Brody