quack vs doc

quack and doc both are nouns.

Word	Noun	Adjective	Verb	Adverb
quack	Yes	Yes	Yes	No
doc	Yes	No	No	No

As nouns, doc is a hypernym of quack; that is, doc is a word with a broader meaning than quack:

quack: an untrained person who pretends to be a physician and who dispenses medical advice
doc: a licensed medical practitioner

Other hypernyms of quack include doctor, Dr., MD, medico, physician, charlatan, mountebank.

quack (noun)	doc (noun)
the harsh sound of a duck	a licensed medical practitioner
an untrained person who pretends to be a physician and who dispenses medical advice

quack (adjective)	doc (adjective)
medically unqualified

quack (verb)	doc (verb)
act as a medical quack or a charlatan
utter quacking noises