What is a bbl slang?

"BBL" in slang most commonly stands for Brazilian Butt Lift. This is a cosmetic surgical procedure that involves transferring fat from other areas of the body (like the abdomen, thighs, or hips) to the buttocks to enhance their size and shape.

It's important to note that because it's a cosmetic procedure, the term is primarily used in conversations about beauty, body image, and plastic surgery. You're unlikely to encounter it in other contexts. The term is widely understood within these specific contexts, though.