What is a prep?

In my eyes most of them are superficial assholes who wear Abercrombie and have nothing better to do than talk about tanning, makeup, and their 'friends' behind their backs. Of course not all of them are complete jerks, and this is only my opinion.

It's probably short for 'preppie'(alternate spelling 'preppy') which is short for 'prep school' and is used as a term of derision.
http://en.wikipedia.org/wiki/Preppie

a prep thinks their so cool.but their all probley just some dykes.a prep is like a imitation of a cheer leader.their happy,excited over and little thing and i believe they scare easily.

I am not sure which "preps" you mean. In school and or college many of the guys are called "preppy" due to the way they dress, their demeanor and education. The other kind of "prep" means preparation for anything, like surgery etc. They tell you things to do, to be prepped.

In my experience a prep has always just meant a form of perparation i.e. a prep school etc.. There may be more meanings in different contexts but i haven't come across any.

A Prep in Australia is a child who is in the grade before grade 1.

Prep, grade 1, grade 2, grade 3, etc.

well....this is comming from a prep who isnt a asshole or a bitch....im actually really nice and carring....but im probably the only prep i know that isnt a bitch...whore...slut...or a complete ass...yes i wear all name brand clothing and yes im spolied....but that dosnt mean anything...i will be friends with anyone no matter what click they are in....but in my eyes what u would call someone who isnt like me would probably be a wanna be prep....real preps represent the school...and they are not asses...like the rest if u ever meet 1 u will know the diffrence....but a deffination for a wanna be prep would be...someone who thinks they are "all that" but really no one likes them... they think they have a ton of friends but when u stop being a "prep" u loose them all ya some friends they had....its someone who thinks that the way they dress is gonna make them popular...it is someone that can get any guy/girl they want....but what most people dont realize about wanna be preps is they are trying to be happy at school just to cover up their home life....ive seen it happen one of my close friends used to be a wanna be prep and her home life wasnt good at all it was always something new...and when she finally stoped putting on the mask to cover it up at school she lost all her friends and everyone that had her back...even me for a while.....it took me a while that it related to me...and they she was now a real prep ready to face the world without hiding anything......so u see what a "prep" is now....