Green’s Dictionary of Slang

arrogance, nerve, gall.

1947		K. Lumpkin Making of a Southerner 86: Could not men recount a hundred tales with slight variations of Negroes ‘becoming very insolent,’ of ‘uppityness,’ ‘sassiness.’.
1974		D. Goines Swamp Man 26: Sees us sittin’ here, then got the uppity not to speak!