Top definition
Someone who is constantly in between being classified as fat or regular sized. One day these people look relatively slender, and the next day they look heavy.
Oprah, Rachel Ray, Brittany Spears(2007)

"Do you see that tweaner at the other side of the bar? I can't tell if she's fat or thin from this angle."
by AlexP September 15, 2007
Get the mug
Get a tweaner mug for your dog Bob.