Olympian Games vs Olympic Games

Olympian Games and Olympic Games both are nouns.

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

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

Olympian Games and Olympic Games: the ancient Panhellenic celebration at Olympia in honor of Zeus; held every 4 years beginning in 776 BC

Olympian Games (noun)	Olympic Games (noun)
the ancient Panhellenic celebration at Olympia in honor of Zeus; held every 4 years beginning in 776 BC	the ancient Panhellenic celebration at Olympia in honor of Zeus; held every 4 years beginning in 776 BC
	the modern revival of the ancient games held once every 4 years in a selected country