An archaic verb meaning to settle (a debt or matter) or to pay back goods/money; akin to 'to settle/finish' in older usage.
昔話には借金を済すために旅に出る男がよく登場する。
In old tales, a man often appears who goes on a journey to settle his debts.
Archaic: to fulfill an obligation of payment; to pay in full.
奉公人は借りを済すため、複数年にわたり働いたと記されている。
It is recorded that the servant worked for several years to repay his debt.