pep pill vs amphetamine

pep pill and amphetamine both are nouns.

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

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

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

Other synonyms of pep pill include speed, upper.

pep pill (noun)	amphetamine (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