lightlessness vs pitch blackness

lightlessness and pitch blackness both are nouns.

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

As nouns, lightlessness and pitch blackness are synonyms defined as:

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

lightlessness (noun)	pitch blackness (noun)
total absence of light	total absence of light