cheer vs chirk up

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

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

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

Other synonyms of cheer include cheer up.

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

cheer (verb)	chirk up (verb)
become cheerful	become cheerful
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