bennie vs pep pill

bennie and pep pill both are nouns.

Word	Noun	Adjective	Verb	Adverb
bennie	Yes	No	No	No
pep pill	Yes	No	No	No

As nouns, pep pill is a hypernym of bennie; that is, pep pill is a word with a broader meaning than bennie:

bennie: a form of amphetamine
pep pill: a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression

Other hypernyms of bennie include amphetamine, speed, upper.

bennie (noun)	pep pill (noun)
a form of amphetamine	a central nervous system stimulant that increases energy and decreases appetite; used to treat narcolepsy and some forms of depression