Chav

Chavs were, according to Cassandra, people like Rose Tyler. (TV: New Earth)

Behind the scenes
Though not specifically defined in the body of Doctor Who fiction, this epithet was perhaps in such broad use in British culture during Rose Tyler's tenure that an in-narrative definition would have been insulting to the BBC One audience. It essentially means a working class, urban youth of lower educational achievement, with a somewhat banal dress-sense and lifestyle.