mediocrity vs doer

mediocrity and doer both are nouns.

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

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

Other hypernyms of mediocrity include actor, worker.

mediocrity (noun)	doer (noun)
ordinariness as a consequence of being average and not outstanding	a person who acts and gets things done
a person of second-rate ability or value