Nonrefundable (adjective)

1. Not eligible for a refund or return.
2. Not able to be recovered.

Origin:

From non- + refundable, formed in the early 20th century.

Examples:

1. The nonrefundable deposit was taken to secure the booking.
2. The ticket was nonrefundable, and could not be returned for a refund.
3. The nonrefundable fee was charged for processing the application.
4. The customers were unhappy about the nonrefundable policy of the company.
5. The nonrefundable payment was made to reserve a spot at the event.