IPA: //ʌˈniːvənnəs//
KK: /ʌˈnivənnəs/
The state or quality of not being level or smooth; it refers to irregularities or inconsistencies in a surface or situation.
The unevenness of the road made it difficult to drive smoothly.
Unevenness → It is formed from "un-" (meaning not) and "even" (from Old English "efen", meaning level or equal) and the suffix "-ness" (meaning the state or quality of). The word "unevenness" refers to the state of being not level or not equal.
Think of 'not' ('un-') being added to 'level' ('even') to remember that 'unevenness' means the quality of being not level.