longer vs doer

longer and doer both are nouns.

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

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

Other hypernyms of longer include actor, worker.

longer (noun)	doer (noun)
a person with a strong desire for something	a person who acts and gets things done

longer (adverb)	doer (adverb)
for more time