medicinal drug vs drug

medicinal drug and drug both are nouns.

Word	Noun	Adjective	Verb	Adverb
medicinal drug	Yes	No	No	No
drug	Yes	No	Yes	No

As nouns, drug is a hypernym of medicinal drug; that is, drug is a word with a broader meaning than medicinal drug:

medicinal drug: (medicine) something that treats or prevents or alleviates the symptoms of disease
drug: a substance that is used as a medicine or narcotic

medicinal drug (noun)	drug (noun)
(medicine) something that treats or prevents or alleviates the symptoms of disease	a substance that is used as a medicine or narcotic

medicinal drug (verb)	drug (verb)
	administer a drug to
	use recreational drugs