redumbulous Share definition Flag A combination of retarded, dumb, and ridiculous; sometimes said as a cover for when saying "retarded" isn't okay. "She is so redumbulous it hurts.""Oh my god, he's so reta---uh, redumbulous!" redumbulous by Lovette Cher February 28, 2010 0 0 Get merch Get the redumbulous mug. Buy Now — $32.95 See more merch