chav

One result of the  media attention is that I've been getting emails from people who've heard or read about the book, usually about individual words and their histories. Chav is one of these. According to the Oxford English Dictionary (OED), it has been used with the sense "a young person of a type characterized by brash and loutish behaviour and the wearing of designer-style clothes (esp. sportswear); usually with connotations of a low social status" since 1998.
There's lots of speculation about the origins of chav, usually involving offensive stereotypes about people who live in Chatham. In reality, chav is from chavvy "a baby; a child", which is originally from an Angloromani word of the same meaning. In other words, Romany-speakers in England used chavvy "child" when they were speaking their own language. By 1886 it was being used in English, apparently among homeless people  first (they were known as tramps at the time). From there it spread into wider dialect use in the south of England. It was picked up by the media in about 2004/5 and is now widely used.
You might have heard chavvy in the lyrics of Hersham Boys by Sham 69 or in Only Fools and Horses. Chavvy "child" is well documented, but if you can find an example of chav in its current sense from before 1998 or of chavvy "like a chav" from before 1999, please do let me know.