Green’s Dictionary of Slang

1. (US black) a naïve, unsophisticated Southern person.

1954		Harper’s Mag. Nov. 36: Corn-bread, bread: a fellow with a Southern accent.
1988		(con. 1940s) C. Bram Hold Tight (1990) 17: Don’t go eyeballing me, Willie Cornbread.

2. (US) anything old-fashioned, sentimental, hackneyed.

1957

H. Simmons Corner Boy 143: Kenny liked boogie-joogie and Scar was not in the mood for digging corn bread.