fiduciary vs steward

fiduciary and steward both are nouns.

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

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

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

fiduciary (noun)	steward (noun)
a person who holds assets in trust for a beneficiary	someone who manages property or other affairs for someone else
	a union member who is elected to represent fellow workers in negotiating with management
	one having charge of buildings or grounds or animals
	an attendant on an airplane
	the ship's officer who is in charge of provisions and dining arrangements

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