What is a punk?

I would like to understand what punk means and stands for as first used in American lingo and then seemed to travel globally to various countries regardless of language. And no I am not looking to know what punk music is or fashion or hairstyle but more as to sociological meaning and placement. Why did 'Dirty Harry' call the criminal a punk? Why do the 80s brat pack movies like The Outsiders have references to some characters as being punks? Why do more figures of authority always refer to a teenage protagonist in films and literature as being punks. What is a punk? Who would be cled as a punk? Why would they be called a punk?