denizen vs organism

denizen and organism both are nouns.

Word	Noun	Adjective	Verb	Adverb
denizen	Yes	No	No	No
organism	Yes	No	No	No

As nouns, organism is a hypernym of denizen; that is, organism is a word with a broader meaning than denizen:

denizen: a plant or animal naturalized in a region
organism: a living thing that has (or can develop) the ability to act or function independently

Other hypernyms of denizen include being.

denizen (noun)	organism (noun)
a plant or animal naturalized in a region	a living thing that has (or can develop) the ability to act or function independently
a person who inhabits a particular place	a system considered analogous in structure or function to a living body