Nonrecoverable is an adjective that describes something that cannot be restored or regained. There are several synonyms for nonrecoverable, including irredeemable, irretrievable, irreversible, and unrecoverable. These words imply that the situation is final and cannot be undone. Irredeemable suggests that there is no possible way to save or rescue the thing or situation. Irretrievable implies that something has been lost or irreparably damaged beyond repair. Irreversible implies that a change has been made that cannot be undone. Lastly, unrecoverable implies that something cannot be regained or retrieved, indicating a permanent loss. All of these words can be used to describe situations of loss, damage, or irreversible change in various contexts.