1. (n.) That which is behind in payment, or which remains unpaid, though due; as arrears of rent, wages, or taxes\; esp. a remainder, or balance which remains due when some part has been paid; arrearage.

2. (adv.) To or in the rear; behind; backwards.

arrear arrears back debts back payments bouncing check break debt decline defalcation default defect defectiveness deferred payments deficiency deficit deficit financing delinquency discontinuity dollar gap due failure falling short gap hiatus imperfection inadequacy indebtedness inferiority insufficiency interval lack lacuna liability missing link need obligation omission outage overdraft short measure shortage shortcoming shortfall slump ullage underage want wantage