darkness vs skin color

darkness and skin color both are nouns.

Word	Noun	Adjective	Verb	Adverb
darkness	Yes	No	No	No
skin color	Yes	No	No	No

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

Other hypernyms of darkness include complexion, skin colour.

darkness (noun)	skin color (noun)
a swarthy complexion	the coloring of a person's face
having a dark or somber color
an unenlightened state
an unilluminated area
absence of light or illumination
absence of moral or spiritual values