foot doctor vs specialist

foot doctor and specialist both are nouns.

Word	Noun	Adjective	Verb	Adverb
foot doctor	Yes	No	No	No
specialist	Yes	No	No	No

As nouns, specialist is a hypernym of foot doctor; that is, specialist is a word with a broader meaning than foot doctor:

Other hypernyms of foot doctor include medical specialist.

foot doctor (noun)	specialist (noun)
a specialist in care for the feet	an expert who is devoted to one occupation or branch of learning
	practices one branch of medicine