mediocrity vs mundaneness

mediocrity and mundaneness both are nouns.

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

As nouns, mundaneness is a hypernym of mediocrity; that is, mundaneness is a word with a broader meaning than mediocrity:

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

Other hypernyms of mediocrity include mundanity, ordinariness.

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