Green’s Dictionary of Slang

1. (US black) an elegant, expensive and prized motorcar.

1973		Cincinnati Enquirier (OH) Mag. 14 Oct. 44/2: Broug or Brougham — Cadillac, luxury car.
1983		R. Klein Jailhouse Jargon and Street Sl. [unpub. ms.].

2. a fellow black man.

1985

T.R. Houser Central Sl. 12: brougham An expression of blood, i.e., close friend, or cuzz, though not as commonly used. A more rakish form of address than cuzz. ‘Brogham, what it be.’.