irretrievable
Word family
Synonym discussion
Sense: adjective/1
All four words describe something that cannot be made right, but they differ in scope and register. Irreparable focuses narrowly on damage or harm that cannot be fixed — you would speak of irreparable damage to a friendship or a reputation. Irreversible describes a one-way change in direction or process, such as an irreversible decision or irreversible climate effects. Unrecoverable is more technical, used for data, files, or financial costs that cannot be regained. Lost is the broadest and most informal of the group: a lost item may simply be misplaced, not necessarily gone forever. For example: 'The divorce caused irreparable harm to the children' (harm-focused) vs. 'The company recorded an unrecoverable debt of two million dollars' (financial/technical) vs. 'Ravi felt the moment was lost and he could not bring it back' (general, less severe).
Common collocations
Etymology
Irretrievable comes from the Latin prefix in- meaning 'not' and retriever, an Old French verb meaning 'to find again' (from re- 'again' + trover 'to find'). The word entered English in the mid-1600s, first used in legal contexts about property that could not be regained.