n. a rate of interest on a debt which is exorbitant and in excess of the percentage allowed by law. Each state sets its own maximum interest rate. Courts will not enforce payment of interest on a loan if the rate is usurious, so a loan may result in being interest free. Charging usury as a practice is a crime, usually only charged if a person makes a business of usury, sometimes called "loan-sharking." Banks and other commercial lenders generally are not subject to anti-usury laws, but are governed by the marketplace and the competitive rates triggered by loan rates to institutions set by the Federal Reserve Bank.