According to several online sources, the general definition of the word priggish is someone who is exceedingly proper, almost arrogantly so, and in an irritating manner. The first character that came to mind right off the bat was Aunt Alexandra; she is always after Scout about how she dresses and behaves, and she is always ranting and raving about the classes of Maycomb, and who is proper and who isn't. However, priggish is such a negative word, and by the end of the novel, Lee has painted a more sympathetic, supportive and kind Alexandra, so I don't like slapping the word priggish on her and walking away, just like that. So, my thoughts turn perhaps to Mrs. Merriweather of the missionary circle. Lee herself describes Merriweather as "the most devout lady in Maycomb," referring to her avidity for religious subjects. But what makes Mrs. Merriweather priggish is that she has her own personal belief system that she announces to absolutely everybody, and anyone who doesn't agree with her, she makes them feel like an absolute heathen. She brazenly and openly states her opinions that the south is better than the north because at least in the south they don't give black people false hope. She rails against Tom's case, displaying open racism and meanness. So, the "arrogant" and "irritating" factors of priggishness apply to her more, along with the more negative connotation that comes along with it. Check out chapter 24, and see what you think of her for yourself. To me, she is the best definition of priggish because she has a very stern set of beliefs and morals, announces them arrogantly as if everyone should agree with her, and is highly irritating and insensitive as she does so. I hope that helps a bit-good luck!