IFMYM Share definition Flag Chat or Text messaging.Abbreviation for:I fucking miss you moron Girl: ifmymBoy: Wut? if what?Girl: It means...I fucking miss you, moron!Boy: Got it...(guess lulz) IFMYM by DarkyFromHell April 16, 2011 0 0 Get merch Get the IFMYM mug. Buy Now — $32.95 See more merch