Green’s Dictionary of Slang

(W.I.) coarse, vulgar; unadorned.

1957		F.G. Cassidy ‘Iteration as a Word-forming Device in Jam. Folk Speech’ in AS XXXII:1 53: raw-chaw, coarse, vulgar.
1995		Francis-Jackson Official Dancehall Dict. 43: Raw-chaw [...] 2. vulgar, unadulterated.