Source : Webster's Revised Unabridged Dictionary (1913)

Irremediable \Ir`re*me"di*a*ble\, a. [L. irremediabilis: cf. F.
   irr['e]m['e]diable. See {In-} not, and {Remediable}.]
   Not to be remedied, corrected, or redressed; incurable; as,
   an irremediable disease or evil.

Source : WordNet®

irremediable
     adj : impossible to remedy or correct or redress; "an irremediable
           error"; "irremediable defects of character" [ant: {remediable}]