Where does “impago” come from?

impago (Spanish) comes from Spanish pago, from Spanish pagar, from Old Spanish pagar, from Latin pācō, from Latin pāx, from Proto-Italic pāks, from Proto-Indo-European péh₂ḱ-s, from Proto-Indo-European peh₂ḱ- — to join, to attach; agreement, settlement.

impago (Spanish): nonpayment