neutral vs achromatic

neutral is a noun but achromatic is not a noun.

Word	Noun	Adjective	Verb	Adverb
neutral	Yes	Yes	No	No
achromatic	No	Yes	No	No

As adjectives, neutral and achromatic are synonyms defined as:

neutral (noun)	achromatic (noun)
one who does not side with any party in a war or dispute

neutral (adjective)	achromatic (adjective)
having no hue	having no hue
possessing no distinctive quality or characteristics
lacking distinguishing quality or characteristics
not supporting or favoring either side in a war, dispute, or contest
having no personal preference
having no net electric charge
having only a limited ability to react chemically; chemically inactive