Graeco-Roman deity vs immortal

Graeco-Roman deity and immortal both are nouns.

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

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

Graeco-Roman deity: a deity of classical mythology
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 Graeco-Roman deity include deity, divinity, god.

Graeco-Roman deity (noun)	immortal (noun)
a deity of classical mythology	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

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