Another (perhaps better) definition is here:
Chav - Wikipedia
Chav is a slang term in popular usage throughout the United Kingdom, and is sometimes used in a derogatory fashion. It refers to a subculture stereotype of a person who is uneducated, uncultured and prone to antisocial or immoral behaviour. The label is typically, though not exclusively, applied to teenagers and young adults of working class or lower-middle class origin. Chav is used for both sexes; a male chav may sometimes be referred to as a chavster and a female as a chavette. It is similar to the United States terms white trash, (although many Chavs are part of multi-ethnic inner city communities like London council estates) and trailer trash or the Australian bogan.