insolvable

adjective
  1. 1

    Impossible to solve; insoluble.

  2. 2

    Incapable of being paid or discharged.

    โ€œan insolvable debtโ€

  3. 3

    Not capable of being loosed or disentangled; inextricable.

Source: https://en.wiktionary.org/wiki/insolvable