Sass-Bag Share definition Flag One who is full of "sass", and never-ending comebacks. Happens frequently with undisciplined children, always with a smart remark. Dude, you never shut up. You're a sass-bag bro. Sass-Bag by Chris Magoo 2 March 8, 2011 0 0 Get merch Get the Sass-Bag mug. Buy Now — $32.95 See more merch