foulness vs darkness

foulness and darkness both are nouns.

Word	Noun	Adjective	Verb	Adverb
foulness	Yes	No	No	No
darkness	Yes	No	No	No

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

Other hypernyms of foulness include dark, wickedness.

foulness (noun)	darkness (noun)
the attribute of having a strong offensive smell	a swarthy complexion
(of weather) the badness of the weather	having a dark or somber color
a state characterized by foul or disgusting dirt and refuse	an unenlightened state
disgusting wickedness and immorality	an unilluminated area
	absence of light or illumination
	absence of moral or spiritual values