1. That may be returned or restored; that is legally to be returned or rendered.

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

• retainable,
• returnalbe,
• refudnable,
• refunable,
• retunable,
• retutneble,
• returbable,
• retrurnable,
• reurnable,
• retrunable,
• returanble,
• returnible,
• futurrable,
• requriable,
• retanable,
• Retainible,
• Ritornalle,
• saturrable,
• returtile,
• returneable

• return ticket,
• return key,
• returning.

The adjective form of the word "returnable" is "returnable".

The plural form of "returnable" is "returnables"

The singular form of the word "returnable" is "returnable". It is already in singular form and can also be used as a collective noun.