Green’s Dictionary of Slang

(orig. US black) to attack verbally, to slander; to be cheeky, to tease.

1969		C. Sellers Where Have All the Soldiers Gone 77: ‘You smart-mouthin’? You tryin’ to say I cut out?’.
1976		R.B. Parker Promised Land 65: Don’t smart-mouth me, man. You wising off at me?
1986		R. Campbell In La-La Land We Trust (1999) 146: Don’t smart-mouth me. What the hell you think, we’re brain-stunned down here?
2005		B. Fitzhugh Pest Control 57: Doing a book report on Jack London’s The Call of the Wild as punishment for smartmouthing his English Lit teacher.