brief, adj. — Green’s Dictionary of Slang

brief adj.

[i.e. ‘no frills’]

(US black) elegant, well-dressed, smart.

1893

H.A. Shands Speech in Mississippi n.p.: Brief [...] used by negros to mean nice, elegant. I once heard a negro tell a young man who had dressed up to go to see his sweet-heart: ‘Boss, you sho looks brief.’ [DARE].