lusterlessness vs flatness

lusterlessness and flatness both are nouns.

Word	Noun	Adjective	Verb	Adverb
lusterlessness	Yes	No	No	No
flatness	Yes	No	No	No

As nouns, lusterlessness and flatness are synonyms defined as:

lusterlessness and flatness: the property of having little or no contrast; lacking highlights or gloss

Other synonyms of lusterlessness include lustrelessness, mat, matt, matte.

lusterlessness (noun)	flatness (noun)
the property of having little or no contrast; lacking highlights or gloss	the property of having two dimensions
	inactivity; showing an unusual lack of energy
	the property of having little or no contrast; lacking highlights or gloss
	a deficiency in flavor
	a want of animation or brilliance