medical specialist vs doctor

medical specialist and doctor both are nouns.

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

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

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

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

medical 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