*Ponders*
I don't think chav's have quite an exact term over in the US, though hoodlum certainly comes close. Personally, I think "
Sand People" are probably closer. It was originally lower class and poorer citizens, and whilst it's still most notable in less affluent areas it's spread somewhat. Think closer to a regression in evolution; people using words such as "innit" and "blud" to form entire conversations which seem meaningless to outsiders. Yes, on their own they're pretty harmless, though they're a territorial beast they don't want to get hurt. I've seen packs of 3 or 4 decide to leave me alone until they've got a couple more to join their ranks, just in case. Many join them by blending in - it's not hard, buy a "burberry" shirt and some jogging bottoms and you're pretty much there, maybe a fake gold chain and some brand name trainers to be on the safe side - and the further you are from this the more likely you are to provoke an attack. Many that blend are actually otherwise perfectly normal, it's just to prevent arousing suspicion. Me walking around with a band shirt and long hair naturally meant I was a frequent target, but like Sand People, "The Chav's are easily startled but they'll soon be back, and in greater numbers." About the only positive thing about chav's are the fact that they aren't racist. They won't pick on a guy for being black, just if they don't conform in a materialistic manner.
EDIT: I believe "Guido" might be a better term than Hoodlum, if that helps.