variability vs unevenness

variability and unevenness both are nouns.

Word	Noun	Adjective	Verb	Adverb
variability	Yes	No	No	No
unevenness	Yes	No	No	No

As nouns, variability and unevenness are synonyms defined as:

variability and unevenness: the quality of being uneven and lacking uniformity

variability (noun)	unevenness (noun)
the quality of being subject to variation	the quality of being uneven and lacking uniformity
the quality of being uneven and lacking uniformity	the quality of being unbalanced