YKWYL Share definition Flag You know what your're like. Used in an often friendly, jocular way when confronted with a companion's behaviour. Person A: "I'm not going out tonight" Person B: "YKWYL" YKWYL by Grim Rob October 18, 2007 0 0 Get merch Get the YKWYL mug. Buy Now — $32.95 See more merch