Just for a larf (and because it didn't necessitate me actually getting up out of my chair, perish the thought) I looked it up on my Mac's built-in dictionary, which calls itself the Oxford American Dictionary. It sez "a person who frequents bars and is often drunk".

I stand well and truly corrected - obviously I didn't hang out in the right places when I lived in the States...

I still think this qualifies as a music thread. The whole original query, and many of the answers, are about the way the word relates to song lyrics.