Bums

I was just over working at the place where the bum hit me up for some change a couple weeks ago. He wasn't there this time but thinking about him got me to wondering: Where did the term "bum" come from? 

Did "bumming" come first, and then it shortened to bum? You know, the guy down on the corner bumming change? Or did is bumming an extension of bum? One of those chicken or the egg things.

Looks like bum came first, according to Yahoo Answers (from 8 years ago): "The word "bum" in this sense of "vagrant or beggar" almost certainly comes from the German "Bummler," meaning "loafer.". 

There you have it. Isn't this blog is a wealth of information?

Now I have to wonder how we came up with the word "bummer"?