That young child dressed in dirty hand-me-downs and running rampant through city streets is an urchin. Street urchins, as they are commonly called, have a reputation for getting into trouble.
Strangely enough, urchin, pronounced "UR-chin," comes from the 13th century French word yrichon, which means “hedgehog,” and is still used as such in parts of England today. As for people who are urchins, perhaps they got the name because at the time, they were so small, wild and many in number — like hedgehogs. The 19th century novelist Charles Dickens wrote about so many fictional urchins, most famously Oliver Twist, that dickens has become a synonym for urchin.