Is Olympiad a proper noun

The compound noun "Olympic Games" is a proper noun, the name of a specific sports competition held every four years in different participating countries.

The Olympic Games are sometimes called the Olympics, also a proper noun.

The Word "Olympic" is a proper adjective derived from the proper noun "Olympia", the name of the region of ancient Greece where the Olympic Games originated.

A proper noun and a proper adjective are always capitalized.