Not having a remedy; not capable of being remedied. from 16th c.
1596, Edmund Spenser, The Faerie Queene, V.11:I driven am to great distresse, And forced to forgoe th'attempt remedilesse.
1603, John Florio, translating Michel de Montaigne, Essays, II.12:As for the rest, this disease is not so easily discovered, except it be altogether extreame and remedilesse; forasmuch as reason marcheth ever crooked, halting and broken-hipt; and with falshood as with truth; and therefore it is very hard to discover her mistaking and disorder.