chav
An American definition of chav because most of these definitions on here are British:

Symptoms of a chav:
Adidas, Air Jordans or any expensive sneakers
White tees

Jerseys
Chains
Baggy jeans that don't fit
A pissed off look on their face
An ipod
An expensive cell phone
Is most likely white
Probably comes from a middle class family but pretends to be ghetto
Listens to rap

Uses the words: mad, tight, retarded, gay, yo, ayo, and often typ3s Lik3 tHiS.
They hate emos and goths, or anyone they think is emo or goth. They often accuse people of being goth even when they're not.
They hate homosexuals
They're very ignorant and arrogant and can't think for themselves, they always do what they're friends are doing
They often vandalize

They fight all the time
They think they're tougher than they really are and accuse people of "runnin' their mouth"
Basically just really stupid neanderthals.
So you're walking down the street and you see a pissed off looking white boy wearing Nike shorts that sag to his knees or baggy jeans. He's wearing a white tee or a jersey of some kind, with a chain or two. He's wearing 200 dollar Air Jordans or Adidas. When you look at him he says, "What the fuck are you staring at?"
He's a chav.