A youth (15-25 ish) who habitually wears a hoody (qv) with the hood up. Probably has a feral aspect and a rather nasty cast to their features. (More than likely due to the combination of bad diet and Crack abuse.)
The typical hoodrat is often a shoplifter, twoc-er, or similar low-life fool.
Avoid them, if only for the smell.
See also: chav
1: "Hoodrats at 4 o'clock, better keep an eye on the valuables."
2: "Shit man, you look like a hoodrat Steve, like some kind of evil hobbit."