Not Fucking Safe For Fucking Work. A way of warning people that the online content you're sharing isn't something they'd want their boss to catch them reading/watching/listening to. Like NSFW but much worse.
Dude, my boss was standing there when I opened that video of you doing the windmill. You need to mark that shit NFSFFW.
by UKpedant October 04, 2013
Can you define these popular missing words?