semidarkness vs darkness

semidarkness and darkness both are nouns.

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

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

Other hypernyms of semidarkness include dark.

semidarkness (noun)	darkness (noun)
partial darkness	a swarthy complexion
	having a dark or somber color
	an unenlightened state
	an unilluminated area
	absence of light or illumination
	absence of moral or spiritual values