stimulant vs drug

stimulant and drug both are nouns.

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

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

stimulant (noun)	drug (noun)
a drug that temporarily quickens some vital process	a substance that is used as a medicine or narcotic
any stimulating information or event; acts to arouse action

stimulant (adjective)	drug (adjective)
that stimulates

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