colorful vs colouring

colorful is not a noun while colouring is a noun.

Word	Noun	Adjective	Verb	Adverb
colorful	No	Yes	No	No
colouring	Yes	No	No	No

colorful (noun)	colouring (noun)
	the act or process of changing the color of something
	a visual attribute of things that results from the light they emit or transmit or reflect
	a digestible substance used to give color to food

colorful (adjective)	colouring (adjective)
having much or varied color
having color or a certain color; sometimes used in combination
striking in variety and interest