sleeping tablet vs soporific

sleeping tablet and soporific both are nouns.

Word	Noun	Adjective	Verb	Adverb
sleeping tablet	Yes	No	No	No
soporific	Yes	Yes	No	No

As nouns, soporific is a hypernym of sleeping tablet; that is, soporific is a word with a broader meaning than sleeping tablet:

sleeping tablet: a soporific drug in the form of a pill (or tablet or capsule)
soporific: a drug that induces sleep

Other hypernyms of sleeping tablet include lozenge, pill, tab, tablet, hypnotic.

sleeping tablet (noun)	soporific (noun)
a soporific drug in the form of a pill (or tablet or capsule)	a drug that induces sleep

sleeping tablet (adjective)	soporific (adjective)
	sleep inducing
	inducing mental lethargy