blackness vs lightlessness

blackness and lightlessness both are nouns.

Word	Noun	Adjective	Verb	Adverb
blackness	Yes	No	No	No
lightlessness	Yes	No	No	No

As nouns, blackness and lightlessness are synonyms defined as:

Other synonyms of blackness include black, pitch blackness, total darkness.

blackness (noun)	lightlessness (noun)
the quality or state of the achromatic color of least lightness (bearing the least resemblance to white)	total absence of light
total absence of light