steward vs guardian

steward and guardian both are nouns.

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

As nouns, guardian is a hypernym of steward; that is, guardian is a word with a broader meaning than steward:

Other hypernyms of steward include defender, protector, shielder.

steward (noun)	guardian (noun)
someone who manages property or other affairs for someone else	a person who cares for persons or property
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