cheer vs cheer up

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

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

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

Other synonyms of cheer include chirk up.

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

Other synonyms of cheer include jolly along, jolly up.

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

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