Olympian vs Olympic

Olympian is a noun but Olympic is not a noun.

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

As adjectives, Olympian and Olympic are synonyms defined as:

Olympian and Olympic: of the region of Olympia in Greece or its inhabitants

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

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