Black market is the sale or distribution of goods or currency in violation of ceiling prices, quotas, rationing, and priorities established by a government. Anyone who buys or sells rationed goods or controlled currency through illegal channels or above the established ceiling prices becomes a dealer in the black market.
Black marketeers deal in secret. They are most successful in countries that cannot produce enough goods to supply all the people’s needs. In times of emergency, such as a war, most governments set up systems of rationing so that everyone receives a fair share at legal prices. Black markets then spring up to sell goods to people who do not care how much they have to pay in order to have more of some luxury. Profits earned in the black market are often substantial.
Black marketing is illegal. A “gray market” deals in the same kinds of goods, at exorbitant prices, but its operators manage to stay within the law.