IWTFY Share definition Flag Acronym for "I wrote this for you" or "I write this for you" The email message recipient was cheered up. The subject of the message was written "IWTFY" and the message body had a smiley emoticon. " :) " IWTFY by Phrase-smith May 5, 2010 0 0 Get merch Get the IWTFY mug. Buy Now β $32.95 See more merch