specialist vs doctor

specialist and doctor both are nouns.

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

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

Other hypernyms of specialist include doc, Dr., MD, medico, physician.

specialist (noun)	doctor (noun)
an expert who is devoted to one occupation or branch of learning	children take the roles of physician or patient or nurse and pretend they are at the physician's office
practices one branch of medicine	a licensed medical practitioner
	a person who holds Ph.D. degree (or the equivalent) from an academic institution

specialist (verb)	doctor (verb)
	give medical treatment to
	alter and make impure, as with the intention to deceive
	restore by replacing a part or putting together what is torn or broken