relaxant vs drug

relaxant and drug both are nouns.

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

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

relaxant (noun)	drug (noun)
a drug that relaxes and relieves tension	a substance that is used as a medicine or narcotic

relaxant (adjective)	drug (adjective)
tending to relax or relieve muscular or nervous tension

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