A moneylender is a person or group who typically offers small personal loans at high rates of interest. The high interest rates charged by them is justified in many cases by the risk involved.
They play an active role in lending to people with less access to banking activities, such as the unbanked or underbanked or in situations where borrowers do not have good credit history. They sometimes lend to people like gamblers and compulsive shoppers who often get into debt.
Many countries have laws in place that requires money lenders to be registered and limits on the interest rates that may be charged. For example in India licensed money lenders are governed by Money Lenders Acts of respective states.