fertility drug vs drug

fertility drug and drug both are nouns.

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

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

fertility drug (noun)	drug (noun)
a drug used to increase a woman's fertility	a substance that is used as a medicine or narcotic

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