instatwat Share definition Flag Insta-twat; an acceptable term used to describe and poke fun at Instagram and Twitter; a snap-chat photo of a vagina; Yo dude you on instatwat again, loser. Or bro she sent me an instatwat. instatwat by Backwards92 April 24, 2014 0 0 Get merch Get the instatwat mug. Buy Now — $32.95 See more merch