color-blind person vs someone

color-blind person and someone both are nouns.

Word	Noun	Adjective	Verb	Adverb
color-blind person	Yes	No	No	No
someone	Yes	No	No	No

As nouns, someone is a hypernym of color-blind person; that is, someone is a word with a broader meaning than color-blind person:

color-blind person: a person unable to distinguish differences in hue
someone: a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential

Other hypernyms of color-blind person include individual, mortal, person, somebody, soul.

color-blind person (noun)	someone (noun)
a person unable to distinguish differences in hue	a human being; person, singular, assertive existential pronoun; pronoun, person, singular; quantifier: assertive existential