inkiness vs achromatic colour

inkiness and achromatic colour both are nouns.

Word	Noun	Adjective	Verb	Adverb
inkiness	Yes	No	No	No
achromatic colour	Yes	No	No	No

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

inkiness: the quality or state of the achromatic color of least lightness (bearing the least resemblance to white)
achromatic colour: a color lacking hue; white or grey or black

Other hypernyms of inkiness include achromatic color.

inkiness (noun)	achromatic colour (noun)
the quality or state of the achromatic color of least lightness (bearing the least resemblance to white)	a color lacking hue; white or grey or black