laxative vs purgative

laxative and purgative both are nouns.

Word	Noun	Adjective	Verb	Adverb
laxative	Yes	Yes	No	No
purgative	Yes	Yes	No	No

As nouns, purgative is a hypernym of laxative; that is, purgative is a word with a broader meaning than laxative:

Other hypernyms of laxative include aperient, cathartic, physic.

laxative (noun)	purgative (noun)
a mild cathartic	a purging medicine; stimulates evacuation of the bowels

laxative (adjective)	purgative (adjective)
stimulating evacuation of feces	strongly laxative