Grease is slang for a bribe: money used to “grease someone’s palm” so that a shady arrangement goes smoothly. The phrase is common far beyond gambling. In a casino, it usually means paying a dealer or another staff member to cheat for a player or look the other way, for example by overpaying a bet, flashing a hole card or ignoring capped chips.
Casinos treat grease as a serious offence. A dealer caught taking a bribe is typically fired on the spot and may face criminal charges, while the player who offered it is escorted out and usually barred. Surveillance teams watch for unusually close dealer–player relationships for exactly this reason.
Insider risk online
Online, the same threat appears as insider fraud or collusion. Role-based access and audit logs for manual balance adjustments in the back office are basic controls.