1. What remains still to pay; generally used in the plural. In arrears, behind in payment.

Nuttall's Standard dictionary of the English language By Nuttall, P.Austin

• arree,
• arres,
• arears,
• arreas,
• arrear,
• arrers,
• arrears,
• arrels,
• arraer,
• zrrear,
• srrear,
• wrrear,
• qrrear,
• arrwar,
• arrsar,
• arrdar,
• Arreer,
• arrens,
• ariar,
• Arreurs

The adjective form of the word "arrear" is "arrears".

The plural form of the word "Arrear" is "Arrears"

The singular form of the word "arrear" is "arrear". The word does not change form when used in the singular.