Arrear

Ar·rear

Arrear

adv.
  1. To or in the rear; behind; backwards. [Obs.]

Arrear

n.
  1. That which is behind in payment, or which remains unpaid, though due; esp. a remainder, or balance which remains due when some part has been paid; arrearage; -- commonly used in the plural, as, arrears of rent, wages, or taxes.
    For much I dread due payment by the Greeks Of yesterday's arrear.
    I have a large arrear of letters to write.
    — J. D. Forbes.

Phrases & Compounds

In arrear
behind; backward; behindhand; in debt.