fum-chum Share definition Flag Fum-Chum is an ebreviation of the two terms; fumbling and chumbraos. It is a Mexican expression used to cuss and swear in agony. Fum-Chum! That nail has impaled my foot. fum-chum by Dr Willisthebest April 27, 2004 0 0 Get merch Get the fum-chum mug. Buy Now — $32.95 See more merch