The Collaborative International Dictionary of English v.0.48:
Irretrievable \Ir`re*triev"a*ble\, a. Not retrievable; irrecoverable; irreparable; as, an irretrievable loss. Syn: Irremediable; incurable; irrecoverable. [1913 Webster]WordNet (r) 3.0 (2006):
irretrievable adj 1: impossible to recover or recoup or overcome; "an irretrievable loss"; "irretrievable errors in judgment" [syn: irretrievable, unretrievable]