two-dimensionality vs flatness

two-dimensionality and flatness both are nouns.

Word	Noun	Adjective	Verb	Adverb
two-dimensionality	Yes	No	No	No
flatness	Yes	No	No	No

As nouns, two-dimensionality and flatness are synonyms defined as:

Other synonyms of two-dimensionality include planeness.

two-dimensionality (noun)	flatness (noun)
the property of having two dimensions	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