sleeping tablet vs hypnotic

sleeping tablet and hypnotic both are nouns.

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

As nouns, hypnotic is a hypernym of sleeping tablet; that is, hypnotic 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)
hypnotic: a drug that induces sleep

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

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

sleeping tablet (adjective)	hypnotic (adjective)
	of or relating to hypnosis
	attracting and holding interest as if by a spell