cheer vs cheerful

cheer is a noun but cheerful is not a noun.

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

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

cheer (adjective)	cheerful (adjective)
	being full of or promoting cheer; having or showing good spirits
	pleasantly (even unrealistically) optimistic

cheer (verb)	cheerful (verb)
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