An illegal market. Bloomberg Financial Dictionary
* * *
* * *
black market UK US noun [C, usually singular] COMMERCE
► an illegal system in which products that are difficult or expensive to buy legally are bought and sold: »
Tickets were selling for up to $800 on the black market.
black market in sth »There is a growing black market in fake branded goods.
black market for sth »Gunmakers have been accused of feeding a black market for illegal handguns.
► an illegal system in which workers are employed for very low wages: »
Some unscrupulous employers take workers on the black market to avoid paying the minimum wage.
Financial and business terms. 2012.