A person who, under their own volition, couch surfs, sleeps on buses and in parks, has poor hygiene, and is often drunk and under the influence of several drugs or household substances for days at a time. They have no concern of success, and are resourceful when pushed hard to accomplish a goal, which is more often than not to score, in either the drug or sexual reference.
The term is not interchangable with homeless, as most street freaks have a place to live if they choose.
It is more akin to urban anarchist, although there is no desire in a street freak to fight for any cause.

When you eat dirt for the first time and leave your family to build a shack in the woods