Green’s Dictionary of Slang

(US black) insincere chatter, flattery, deceit.

1897		Ade Pink Marsh (1963) 171: She’s took a lot of at co’n f’m ’em cullud boys.
1902		P.L. Dunbar Jest Of Fate (1903) 175: What do you want to give her all that co’n for? She’ll never get in.
1954		J.D. MacDonald All These Condemned (2001) 118: She would make traditional bleating sounds for you, but with that same trace of corn in her voice.
1961		R.A. Norton Through Beatnik Eyeballs 39: Now this strike me as far from corn in any way.
1970		San Diego Sailor 1: He didn’t bother to interrupt the corn I was giving out about the weather.
1978		S. Longstreet Straw Boss (1979) 279: Spouting the same old corn about the workers.
2005		J. Stahl I, Fatty 269: In this town you’re either corn or firecrackers.