Olympian vs Olympic god

Olympian and Olympic god both are nouns.

Word	Noun	Adjective	Verb	Adverb
Olympian	Yes	Yes	No	No
Olympic god	Yes	No	No	No

As nouns, Olympian and Olympic god are synonyms defined as:

Olympian and Olympic god: a classical Greek god after the overthrow of the Titans

Other synonyms of Olympian include Twelve Olympians.

Olympian (noun)	Olympic god (noun)
an athlete who participates in the Olympic games	a classical Greek god after the overthrow of the Titans
a classical Greek god after the overthrow of the Titans

Olympian (adjective)	Olympic god (adjective)
of or pertaining to the greater gods of ancient Greece whose abode was Mount Olympus
of the region of Olympia in Greece or its inhabitants