chirk up vs cheer

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

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

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

Other synonyms of chirk up include cheer up.

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

chirk up (verb)	cheer (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