powder blue vs chromatic

powder blue is a noun but chromatic is not a noun.

Word	Noun	Adjective	Verb	Adverb
powder blue	Yes	Yes	No	No
chromatic	No	Yes	No	No

powder blue (noun)	chromatic (noun)
a pale blue color with grey in it

powder blue (adjective)	chromatic (adjective)
of a moderate to pale blue or purplish blue	being or having or characterized by hue
	based on a scale consisting of 12 semitones
	able to refract light without spectral color separation