That can not be paid: as, impayable debts or obligations.
Beyond payment; priceless.
The Century Dictionary (Public Domain)
Use "impayable" in a sentence
"Another famous "impayable" was the coffin-cart man who came on occasions to drive the men to their last resting place."
"Both the Colonels tried to tell her; but it was the younger one with the moustache (the one who had said that Jimmy was _ "impayable" _) who satisfied her."
"I think the head must have belonged to some heathen - a Christian could not have looked so; then there was the editor of the 'Liverpool Times,' who read the 'Athenæum' with a grim, 'tomahawk look,' and there was a small specimen of Young England who talked incessantly in a way altogether 'impayable' till his uncle, a mild, elderly man, said: 'All peas grow above their sticks' - which set me off laughing till I had the comfort to see the Young England fairly out of countenance."