Black market
A black market, underground economy, or shadow economy is a market in which goods or services are traded illegally. The key distinction of a black market trade is that the transaction itself is illegal. The goods or services themselves may or may not be illegal to own, or to trade through other, legal channels. Because the transactions are illegal, the market itself is forced to operate outside the formal economy that is supported by the established state power. Common motives for operating in black markets are to trade contraband, avoid taxes and regulations, or skirt price controls or rationing. Typically the totality of such activity is referred to with the definite article as a complement to the official economies, by market for such goods and services, e.g. "the black market in bush meat".
The black market is distinct from the grey market, in which commodities are distributed through channels which, while legal, are unofficial, unauthorized, or unintended by the original manufacturer, and the white market.