Roman deity vs immortal

Roman deity and immortal both are nouns.

Word	Noun	Adjective	Verb	Adverb
Roman deity	Yes	No	No	No
immortal	Yes	Yes	No	No

As nouns, immortal is a hypernym of Roman deity; that is, immortal is a word with a broader meaning than Roman deity:

Roman deity: a deity worshipped by the ancient Romans
immortal: any supernatural being worshipped as controlling some part of the world or some aspect of life or who is the personification of a force

Other hypernyms of Roman deity include deity, divinity, god.

Roman deity (noun)	immortal (noun)
a deity worshipped by the ancient Romans	any supernatural being worshipped as controlling some part of the world or some aspect of life or who is the personification of a force
	a person (such as an author) of enduring fame

Roman deity (adjective)	immortal (adjective)
	not subject to death