cheer vs pep up

cheer is a noun but pep up is not a noun.

Word	Noun	Adjective	Verb	Adverb
cheer	Yes	No	Yes	No
pep up	No	No	Yes	No

As verbs, cheer and pep up are synonyms defined as:

Other synonyms of cheer include barrack, exhort, inspire, root on, urge, urge on.

cheer (noun)	pep up (noun)
the quality of being cheerful and dispelling gloom
a cry or shout of approval

cheer (verb)	pep up (verb)
become cheerful	make more interesting or lively
spur on or encourage especially by cheers and shouts	spur on or encourage especially by cheers and shouts
show approval or good wishes by shouting
cause (somebody) to feel happier or more cheerful
give encouragement to