(a.) Not capable of being recovered, regained, or remedied; irreparable; as, an irrecoverable loss, debt, or injury.

ago antiquated antique beyond recall beyond remedy blown over by bygone bypast cureless dated dead dead and buried deceased defunct departed elapsed expired extinct finished forgotten gone gone glimmering gone-by has-been immedicable incorrigible incurable inoperable irreclaimable irredeemable irreformable irremediable irreparable irretrievable irreversible irrevocable lapsed lost no more obsolete over passe passed passed away past past hope past praying for remediless ruined run out terminal undone unmitigable unrelievable unsalvable unsalvageable vanished wound up