mundanity vs mediocrity

mundanity and mediocrity both are nouns.

Word	Noun	Adjective	Verb	Adverb
mundanity	Yes	No	No	No
mediocrity	Yes	No	No	No

As nouns, mediocrity is a hyponym of mundanity; that is, mediocrity is a word with a more specific, narrower meaning than mundanity:

mundanity: the quality of being commonplace and ordinary
mediocrity: ordinariness as a consequence of being average and not outstanding

Other hyponyms of mundanity include averageness, expectedness, commonness, commonplaceness, everydayness.

mundanity (noun)	mediocrity (noun)
the quality or character of being intellectually sophisticated and worldly through cultivation or experience or disillusionment	ordinariness as a consequence of being average and not outstanding
the quality of being commonplace and ordinary	a person of second-rate ability or value