fiduciary vs trustee

fiduciary and trustee both are nouns.

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

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

fiduciary: a person who holds assets in trust for a beneficiary
trustee: a person (or institution) to whom legal title to property is entrusted to use for another's benefit

Other hyponyms of fiduciary include conservator, administrator, executor, liquidator, receiver, steward, legal guardian.

fiduciary (noun)	trustee (noun)
a person who holds assets in trust for a beneficiary	a person (or institution) to whom legal title to property is entrusted to use for another's benefit
	members of a governing board

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