A player that knows how to play their game properly, and competently along with have accrued a good amount of knowledge of said game to share with lower-level players. @WAZAAAAA That's a Super Saiyan player. That's way beyond "high-level".
A player who has 3 random capital letters and a vertical slash before their handle Ex. HDmonitorlizard = average casual player RND | HDmonitorlizard = high level player