Someone who spends the greater part of their time in bars or other drinking establishments. Primarily heard in US, South Africa. You get to know the people in these places when you're a barfly like me.
barfly
1. n. a person who frequents bars. Who will trust the word of an old barfly like Willy?
2. n. a drunkard. Some barfly staggered out of the tavern straight into the side of a car.