achromatic vs neutral

achromatic is not a noun while neutral is a noun.

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

As adjectives, achromatic and neutral are synonyms defined as:

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

achromatic (adjective)	neutral (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