allergist vs doc

allergist and doc both are nouns.

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

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

Other hypernyms of allergist include doctor, Dr., MD, medico, physician.

allergist (noun)	doc (noun)
a physician skilled in the diagnosis and treatment of allergies	a licensed medical practitioner