Black Market
‘Black Market’ is typically used to infer an illegal, underground or shadow market, that operates outside normal rules and regulations, and where the trade of goods or services may be prohibited by law.
Why it matters
Moving away from terms which infer positive or negative connotations associated to colour and colour binary (e.g. Black = Bad and White = Good) to distance from cultural views of good & evil, especially related to skin colour or appearance. Specifically, this associates 'black' with wrongdoing and illegal activity.
Instead try saying:
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