GAFGO Share definition Flag (noun) acronym of Good At First Glance Only. A person who you are initially attracted to but, as you look more closely, you then find unattractive. Cameron Diaz came on and I thought, "wow!", but she's just a GAFGO. GAFGO by Jehannum August 30, 2013 0 0 Get merch Get the GAFGO mug. Buy Now — $32.95 See more merch