colourful vs indigo

colourful is not a noun while indigo is a noun.

Word	Noun	Adjective	Verb	Adverb
colourful	No	Yes	No	No
indigo	Yes	Yes	No	No

colourful (noun)	indigo (noun)
	a blue-violet color
	deciduous subshrub of southeastern Asia having pinnate leaves and clusters of red or purple flowers; a source of indigo dye
	a blue dye obtained from plants or made synthetically

colourful (adjective)	indigo (adjective)
having much or varied color	having a color between blue and violet
striking in variety and interest
having color or a certain color; sometimes used in combination