purple vs colourize

purple is a noun but colourize is not a noun.

Word	Noun	Adjective	Verb	Adverb
purple	Yes	Yes	Yes	No
colourize	No	No	Yes	No

As verbs, colourize is a hypernym of purple; that is, colourize is a word with a broader meaning than purple:

Other hypernyms of purple include color, color in, colorise, colorize, colour, colour in, colourise.

purple (noun)	colourize (noun)
(Roman Catholic Church) official dress of a cardinal; so named after the Tyrial purple color of the robes
a color between red and blue
(in ancient Rome) position of imperial status

purple (adjective)	colourize (adjective)
of a color intermediate between red and blue
belonging to or befitting a supreme ruler
excessively elaborate or showily expressed

purple (verb)	colourize (verb)
color purple	add color to
become purple