A male British person of (generally) low socio-economic status with a characteristic clothing style, dialect, and mode of consumer activity.
A chav is generally cunning and resourceful and invokes fear amongst his more passive and uncreative contemporaries. The character the "artful dodger" from Dickens' "Oliver Twist" represents the archetypal chav: poor and lacking in ambition, but clever, witty, and fond of creative-poetic language. The authentic "cockney", long since vanished from London, might also be considered a type of proto-chav.
The term "chav" is almost exclusively used in a derogatory sense by out-group persons, most commonly lower or middle-class British persons actively seeking to establish a more prestigious socio-economic status and the corresponding identity.
The term - and the emotional and negative connotations associated therewith - (see the vast majority of the other definitions above) can be considered the latest manifestation of the typically rigid British conception of class-consciousness.
Setting: public space in any English city. Two pedestrians are approached by a young person dressed in a track suit and a "Burberry" hat.
"Oi, gimme a fag, geezer"
"a fuckin' cig, mosha"
"Oh, sorry, I don't smoke"
"'id I say you should talk? Shut the fuck up and get out outta my sight"
Two pedestrians continue on their way. The first, non-smoking pedestrian, seeks to counter his humiliation by addressing the second pedestrian: