Green’s Dictionary of Slang

(US black) an ostentatious tan-coloured suit of clothes.

1941		D. Burley N.Y. Amsterdam News 7 June. 13: I’m gonna get a honkin’ brown [...] an’ it’s gonna have a pin stripe in it.
1944		‘Jiver’s Bible’ in D. Burley Orig. Hbk of Harlem Jive.