refundable
Concise Oxford English Dictionary © 2008 Oxford University Press:
refund
▶verb /rɪˈfʌnd/ pay back (money).
■ pay back money to.
▶noun /ˈriːfʌnd/ a refunded sum of money.– derivatives
refundable adjective.
refundable adjective.
– origin ME (also in the sense ‘pour back’): from OFr. refonder or L. refundere, from re- ‘back’ + fundere ‘pour’, later assoc. with fund.
'refundable' also found in these Oxford entries:

