arrears

arrears
    n 1: the state of being behind in payments; "an account in
         arrears"
    2: an unpaid overdue debt
    

30 Moby Thesaurus words for "arrears":
      arrear, arrearage, back debts, back payments, bouncing check,
      decline, defalcation, default, defectiveness, deferred payments,
      deficit, deficit financing, delinquency, dollar gap, due, failure,
      falling short, imperfection, inadequacy, indebtedness, inferiority,
      insufficiency, liability, overdraft, short measure, shortage,
      shortcoming, shortfall, slump, underage