cannot be undone; irreversible; can't be recovered from
Used when a mistake, loss, or damage is permanent and cannot be fixed or compensated. Often implies a serious, regrettable situation.
See also: 取り返しのつかない
Once lost, trust cannot be regained.
This failure is irreversible.
Variant with 取返し instead of 取り返し; less common but valid.
Phrase composed of 取り返し (noun form of 取り返す, 'to recover') + が + つかない (negative potential of 付く, 'to be attached/established'), literally 'recovery cannot be established'.