The BBC website tells us that the latest edition of the OED includes 1,500 new words, including chav, which is defined as "a young working class person who dresses in casual sports clothing".
This is wikipedia’s view on things: "Chav refers to a subculture stereotype of a person who is uneducated, uncultured and prone to antisocial or immoral behavior. The label is typically, though not exclusively, applied to teenagers and young adults of white working-class or lower-middle class origin. Essentially very few self-identify with these labels and groupings; rather, they are used by those on the outside to categorise those supposedly conforming to the stereotype, which is marked by the similarity of trends in clothing and behaviour. The essential stereotype is of being loudly lower-class, with ‘class’ defined by taste rather than income."
This definition is much more complete; it makes it clear that this is an attempt by society to define and classify one specific social group. It is also a convenient way to ostracise a whole segment of a population, formed of lots of different individuals who are linked by some behaviour trends, which are rather superficial and only part of their story. This "chav" label is quite damning; once it’s been stuck on someone, it is unlikely that this person will be taken seriously at all, she or he has been branded and will likely be dismissed as useless or a joke, regardless of his or her personal history.
This is part of society’s lazy way of dealing with different segments of the population; it provides handy one-size-fits-all categories for geeks, toffs, bible bashers, hippies, pikeys et al. while keeping them at a safe distance, so there’s no need to try and understand or, god forbid! engage with these people. Is the use of the word chav part of an attitude that could be described as a form of social racism?