amphetamine vs pep pill

amphetamine and pep pill both are nouns.

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

As nouns, amphetamine and pep pill are synonyms defined as:

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

Other synonyms of amphetamine include speed, upper.

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