black market
noun [ C, usually singular ]
COMMERCE ukusan 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.