Definition of "immedicable"

Here love receiv'd immedicable harmes, / And was dispoiled of his daring armes.

1650, John Donne, Elegie XVII

wounds immedicable / Ranckle, and feſter, and gangrene, / To black mortification.

1671, John Milton, “Samson Agonistes, […].”, in Paradise Regain’d. A Poem. In IV Books. To which is Added, Samson Agonistes, London: […] J. M[acock] for John Starkey […], page 42

The beastHas a loud trumpet like the Scarabee,His crookèd tail is barbed with many stings,Each able to make a thousand wounds, and eachImmedicable; from his convex eyesHe sees fair things in many hideous shapes,And trumpets all his falsehood to the world.

1820, Percy Bysshe Shelley, Oedipus Tyrannus; Or, Swellfoot The Tyrant: A Tragedy in Two Acts