1. A person who balances several, high-dollar, personal credit accounts and lives an upper-middle class lifestyle despite never having cash on hand.
2. One who never has money and always "owes you one"
"Sure, Muffy and Bif live in that brand new McMansion, drive new Beemers and have two kids at Swanky U , but have you ever been to Burger King with them? They're total creditistas."