achromatic vs off-white

achromatic is not a noun while off-white is a noun.

Word	Noun	Adjective	Verb	Adverb
achromatic	No	Yes	No	No
off-white	Yes	Yes	No	No

achromatic (noun)	off-white (noun)
	a shade of white the color of bleached bones

achromatic (adjective)	off-white (adjective)
having no hue	of something having a color tending toward white