Slick as a Gnat's Ass Share definition Flag An unusually suave female possessed of a kind of amiable alacrity. Well, ain't she slick as a gnat's ass!!! Slick as a Gnat's Ass by Aziz Ibrahim November 24, 2009 0 0 Get merch Get the Slick as a Gnat's Ass mug. Buy Now — $32.95 See more merch