Wiktionary
unhealable
a. That cannot be healed.
Usage examples of "unhealable".
They could not proceed in this condition, especially as the old leak under the buttock had opened up again like an unhealable wound.
But he wonders if the things he is seeing, the things he has seen since before dawn, will slash an unhealable wound through his very soul, if his spirit will bleed and wither and die from the agony of it.
Half of one foot was gone, gnawed away, and in the place of the other was nothing but an unhealable wound.