tricolor vs colorful

tricolor is a noun but colorful is not a noun.

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

tricolor (noun)	colorful (noun)
a flag having three colored stripes (especially the French flag)

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