argent vs achromatic

argent is a noun but achromatic is not a noun.

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

argent (noun)	achromatic (noun)
a metal tincture used in heraldry to give a silvery appearance

argent (adjective)	achromatic (adjective)
of lustrous grey; covered with or tinged with the color of silver	having no hue