fiduciary vs doer

fiduciary and doer both are nouns.

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

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

Other hypernyms of fiduciary include actor, worker.

fiduciary (noun)	doer (noun)
a person who holds assets in trust for a beneficiary	a person who acts and gets things done

fiduciary (adjective)	doer (adjective)
relating to or of the nature of a legal trust (i.e. the holding of something in trust for another)