pitch blackness vs lightlessness

pitch blackness and lightlessness both are nouns.

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

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

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

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