quack
noun
°The sound made by a duck.
"Did you hear that duck make a quack?"
°A fraudulent healer or incompetent doctor of medicine, an impostor who claims to have qualifications to practice medicine.
"That doctor is nothing but a lousy quack!"
verb
°To make a noise like a duck.
"The more breadcrumbs I threw on the ground, the more they quacked."
°To practice, commit quackery.
adjective
°falsely presented as having medicinal powers.