Un-Radd Share definition Flag Something that is not good; opposite of radd. See radd. Girl 1: "Those GIR shoelaces are so radd!!" Girl 2: "I told you, Zim is better, those are UN-RADD." Un-Radd by Tallest Josie April 27, 2008 0 0 Get merch Get the Un-Radd mug. Buy Now — $32.95 See more merch