A unique name for a really hot girl with big tits that is really good at certain things. This girl doesn't take shit from anyone and will fuck you up if you mess with her. People with this name can be very moody, but they do have a very nice sensitive side, and are very good in bed. A well known nickname for people named Betsy is Betsy Wetsy.
"Damn, look at that betsy walking down the street over there!"
"That girl is about to get the betsy knocked out of her if she doesn't stop being such a slut"