NMNFO Share definition Flag When anoying friends ask "the" fucking question.YOU NEED A GOOD REPLY!Means "Not Much Now Fuck Off" Hey wuu2?NMNFO!Ok calm down!FO NMNFO by Personasal October 25, 2009 0 0 Get merch Get the NMNFO mug. Buy Now — $32.95 See more merch