Super Hick slang for the Moderate Hick slang word, "ain't."
"I hain't done a nary thang!"
A contraction of have/has not. It arose in the 1800s in the American South, and it's prevalent in Mark Twain literature. It's still used some by old people and really rural people, but it's largely a dead phenomenon.
-I hain't been anywhere today.
-Hain't you got anything better to do?