monochromasy vs color blindness

monochromasy and color blindness both are nouns.

Word	Noun	Adjective	Verb	Adverb
monochromasy	Yes	No	No	No
color blindness	Yes	No	No	No

As nouns, color blindness is a hypernym of monochromasy; that is, color blindness is a word with a broader meaning than monochromasy:

monochromasy: complete color blindness; colors can be differentiated only on the basis of brightness
color blindness: genetic inability to distinguish differences in hue

Other hypernyms of monochromasy include color vision deficiency, colour blindness, colour vision deficiency.

monochromasy (noun)	color blindness (noun)
complete color blindness; colors can be differentiated only on the basis of brightness	genetic inability to distinguish differences in hue