/ɪˈliːɡəl treɪd/ – noun
Definition: Buôn bán bất hợp pháp.
A more throughout explanation: the activity or business of buying, selling or exchanging illegal goods or services between people or countries; the activity or business of buying, selling or exchanging illegal goods or services between people or countries in an illegal way
Example: Police are looking into the illegal trade in tiger parts on the internet.