Stiff-Nasty Share definition Flag A word meaning "awesome." or "Sick." It's basically used to describe something, but can also be used to describe someone. YO, that car is fucking stiff-nasty brooo! I would so trade in my Mercedes for it! Stiff-Nasty by WaNtEdAmErIcAn December 2, 2010 0 0 Get merch Get the Stiff-Nasty mug. Buy Now — $32.95 See more merch