"UP-ITY" is a Southern Slang term used to describe people who think (or behave as though they think) they are better than other people and/or look down on others due to social status, education (or a lack there-of) , intelligence, attractiveness or economic means. People with money, in the South, are typically referred to as "uppity" by people who lack means. (ie..The Haves and the Have Nots) "Uppity" has no reference to race, it is primarily directed at (social)CLASS and is used (safe to say) equally by old school African Americans as well as Caucasian. It was a term which was very popular through the 1960s but has lost commonality in favor of more modern language.
There she goes acting all up-ity.