cheerful vs cheerfulness

cheerful is not a noun while cheerfulness is a noun.

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

cheerful (noun)	cheerfulness (noun)
	the quality of being cheerful and dispelling gloom
	a feeling of spontaneous good spirits

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