A Person who attends a Private school. (Public school in the United Kingdom)
Can be derrogatory *rolls eyes* because people have no time to do anything worthwhile except tease eachothers schools.
A: Hey look there's Belinda.
B: Whose that? She doesn't go to school with us does she?
A: Nah, she's a Private Schooler.
B: ARGH Private Schoolers!
A: Grow Up.