Unrepaid is defined as something that has not been paid back or settled. Some synonyms for unrepaid include unpaid, owing, outstanding, unsettled, past due, in arrears, delinquent, and unreturned. These words can be used to describe different types of debts or obligations, from unpaid loans and credit card balances to overdue bills and rental payments. Depending on the context, some of these synonyms may be more appropriate than others. For example, "past due" and "in arrears" are often used in reference to bills that are overdue, while "unreturned" may be used to describe items that have not been given back or exchanged.