Definition: To utter a sound like the cry of a duck.
Definition: To make vain and loud pretensions; to boast.
Definition: To act the part of a quack, or pretender.
Definition: The cry of the duck, or a sound in imitation of it; a
hoarse, quacking noise.
Definition: A boastful pretender to medical skill; an empiric; an
ignorant practitioner.
Definition: Hence, one who boastfully pretends to skill or knowledge of
any kind not possessed; a charlatan.
Definition: Pertaining to or characterized by, boasting and pretension;
used by quacks; pretending to cure diseases; as, a quack medicine; a
quack doctor.