excessive in-game spending; whaling
Slang used in gaming communities for spending large amounts of money on in-game purchases, often to the point of being considered unhealthy or extreme.
He spends excessively on social games to maintain a top ranking.
Whales are an important source of revenue for the game operators.
Compound of 廃 (hai, 'ruin' or 'abandonment') and 課金 (kakin, 'billing' or 'in-app purchase'), suggesting spending so much it leads to ruin. The exact origin is uncertain, but it likely emerged from online gaming slang.