A chav is anyone who meets 2 or more of the following criteria:
1)You frequently drink stella
2)You own one or more item of clothing with a burberry pattern
3)You live on, or know more than two people who live on a council estate
4)You listen to hip hop, r'n'b or drum'n'bass
5)You have ever shouted at/abused an OAP or property belonging to an OAP
6)(Boys only) You have a body kit/fluffy dice/a fake spoiler on your car
7)(Girls only) You have 2 kids by the age of 16
Basically, chavs are
the lowest level of civilization, on par with bacteria and worse than what Americans would call "trailer trash".