hasai Share definition Flag 1. So fucking cool it must be from the future. 2. All around awesome. 3. Not sucking 4. In agreement 1. That's hasai! 2., 3., 4. Guy 1: that chick is so hot! Guy 2: Hasai! hasai by B00CH December 30, 2007 0 0 Get merch Get the hasai mug. Buy Now — $32.95 See more merch