greenness vs chromatic colour

greenness and chromatic colour both are nouns.

Word	Noun	Adjective	Verb	Adverb
greenness	Yes	No	No	No
chromatic colour	Yes	No	No	No

As nouns, chromatic colour is a hypernym of greenness; that is, chromatic colour is a word with a broader meaning than greenness:

Other hypernyms of greenness include chromatic color, spectral color, spectral colour.

greenness (noun)	chromatic colour (noun)
green color or pigment; resembling the color of growing grass	a color that has hue
the lush appearance of flourishing vegetation
the state of not being ripe