A term applied to 3 British New Wave musicians in the late 1970s—Elvis Costello, Joe Jackson, and Graham Parker. The term was due to their alter-egos as eternally pissed off young men who were fed up with the state of society. Their manic stage shows and frantic music helped quite a bit, as well.
Joe Jackson had the funniest thing to say about this once in concert (it was 10 years ago, I'm paraphrasing):
"They used to call me an angry young man and I never understood it. It sounds like I would get up every morning, storm out of bed, brush my teeth really angrily, throw my breakfast at the wall, and then go out and made a record! It's not like that at all!"