Nolo's Plain-English Law Dictionary

Usury

Extending credit at an exorbitant or illegally high interest rate. States set their own maximum interest rates, and courts will not enforce payment of interest on a loan if the rate is usurious. Most credit card issuers are based in states with no usury laws or caps on credit card interest rates.
NOLO-web4:DRU1.6.8.23.20160804.41205