A combination of "sexy" and "rezzy". The self mindset of a Native American girl who lives on the reservation. She is overweight, yet wears tight revealing clothes, lots of make up and does her hair up. Meanwhile to everyone else, it is appalling.
At the pow wow:
Bill: Look at her, that is disgusting, her rolls are falling out of those clothes that should be on someone 4 sizes smaller than her.
Betty: Ya, she thinks she is Sezzy.