hoon, n, colloquial 1. a loutish, aggressive, or surly youth; 2. a foolish or silly person; 3. one who lives off the proceeds of prostitution.
My own understanding of it has always been based on regarding it as an abbreviation of the word "hooligan."
It has also become used as a verb in recent years, "hooning" usually referring to youths or young men showing off their motor vehicles - sometimes to the extent of blocking off public roads for drag races, etc.
"battler" has different connotations. I have never heard it used to describe a prostitute, which seems to be the implication in Q's post, although that meaning is also given in the Macquarie, along with:
n, 1. one who struggles continually and persistently against heavy odds; 2. a conscientious worker, esp. one living at subsistence level; 3. an itinerant worker reduced to living as a swagman; 4. (colloq) a prostitute.