Related Clues:

• Unpaid debt
• Overdue sum
• Overdue payment
• State of lateness
• Unpaid bill
• Unfulfilled duty
• Sum of money owed
• Amount of debt, old-style
• Overdue thing
• Overdue debt
• Unpaid amount
• Delinquency word more commonly heard in the plural
• Backlog as of work
• A rarer kind of backlog
• Artist back-to-back?