A young person from a rich or well-off family who goes to an expensive school and/or who wears expensive, tidy clothes. Preppies are often mistaken for Valley-Girls; the annoying "LIKE, OH MY GOD!" people that prefer trends over class and make your skin crawl, and highschool popular kids, which are even worse because they are often rude and dress like sluts. True preppies are very nice and approachable down to earth people. They were raised well and are equiped with common decency and manners.
The Bush Daughters would be preppy if they would quit acting like morons.