The female version of a douchebag, i.e. guys wearing polo shirts, popped collar, etc. A ball sack is a female that wears inappropriately tight clothing, typically has bleach blonde, damaged hair, acts stupid because they think it's cute, has a fake tan and nails, and has a very high opinion of themselves. They generally assume everyone wants to be like them and guys want them but truthfully, everyone looks at them because they are so pathetic. Other identifiers: hoop earrings, designer sunglasses, obsessed with labels, too much eyeliner, nail art, pink lip gloss, sense of entitlement, lack of ambition, likes meatheads, is a lush, and often quite slutty.