Greco-Roman deity vs god

Greco-Roman deity and god both are nouns.

Word	Noun	Adjective	Verb	Adverb
Greco-Roman deity	Yes	No	No	No
god	Yes	No	No	No

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

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

Greco-Roman deity (noun)	god (noun)
a deity of classical mythology	a material effigy that is worshipped
	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 man of such superior qualities that he seems like a deity to other people