luminosity vs luminousness

luminosity and luminousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
luminosity	Yes	No	No	No
luminousness	Yes	No	No	No

As nouns, luminosity and luminousness are synonyms defined as:

luminosity and luminousness: the quality of being luminous; emitting or reflecting light

Other synonyms of luminosity include brightness, brightness level, light, luminance.

luminosity (noun)	luminousness (noun)
the quality of being luminous; emitting or reflecting light	the quality of being luminous; emitting or reflecting light