FMFSL Share definition Flag an acronym standing for Fuck My Fucking Shit Life. It is to be used in situations when Fuck My Life (FML) is not deemed severe enough. Paige: You know she has a really hairy belly? Ethan: Eww! FMFSL! No more wanking over her. FMFSL by Ranga O_o December 14, 2009 0 0 Get merch Get the FMFSL mug. Buy Now — $32.95 See more merch
