flatness vs two-dimensionality

flatness and two-dimensionality both are nouns.

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

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

Other synonyms of flatness include planeness.

flatness (noun)	two-dimensionality (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