A girl who hangs out in a bar to act as a companion to men customers and encourage them to buy lots of drinks. She may be employed in this by the bar owner or work freelance. She may be 'bought off' for the evening and this may involve a 'barfine', technically to compensate the bar owner for the loss. Thereafter she operates just as a prostitute does, and often will provide vaginal, anal and oral sex in your local hotel. In some hotels in some resorts there is a 'joiner' fee payable at the foyer before they will allow you to bring the girl back to your room.
"...this place is where the best looking bargirls are, over 200 on the books, not all working at the same time but on the payroll. Any given day there will be 50 to 100 of them working, some of the best looking in Patong, and lots of freelancers." Patong is a popular sex-tourism resort in Thailand along with Bangkok, Patpong, Pattaya and Phuket.
A Young Woman Who Works in a GoGo Bar in the "Entertainment" Districts in Southeast Asian tourist destinations. Not necesarilly a prostitute.
The term is also used as an insult by young women in said regions, to indicate that another young woman is low class, vulgar, or a prostitute.
"Siriporn act like Bar Girl"