fwacky Share definition Flag Fucking Wacky, not just plain wacky. Totally weird and/or cool. (Always a positive, never a negative.) "The vibrations feel fwacky against my ass and I'm pretty sure I like it." fwacky by ultrascott December 26, 2008 0 0 Get merch Get the fwacky mug. Buy Now — $32.95 See more merch