Lewis & Short

faenē̆bris (less correctly fēn-, foen-), e, adj. [faenus; cf. Paul. ex Fest. pp. 86 and 94], of or relating to interest or usury: leges, Liv. 35, 7: res, the matter of interest and debts, the relations between debtor and creditor, id. 7, 21: pecunia, lent on interest, Suet. Calig. 41: malum, Tac. 6, 16.