noun
Typically used for official refunds of taxes, social insurance premiums, or public fees. In everyday contexts, 払い戻し is more common for general refunds.
確定申告をしたら、還付金が口座に振り込まれた。
After filing my tax return, the refund was deposited into my account.
Compound of 還付 (return, restore) and 金 (money). The exact historical derivation is uncertain, but the word is conventionally associated with official reimbursements.