TTFSM Share definition Flag Acronym for "thank the flying spaghetti monster". Often used by agnostics, atheists, and other pastafarians instead of saying "thank god". We made it to the championship round! TTFSM!TTFSM, she wasn't hurt in the car accident. TTFSM by truemyth September 24, 2011 0 0 Get merch Get the TTFSM mug. Buy Now — $32.95 See more merch