wtgb Share definition Flag An IM, texting, or LOL-speak phrase expressing disbelief. More commonly known as an acronym standing for "What the garbage, Batman?" My dad won't let me pierce my forehead. wtgb.Your mom just asked me out. wtgb. wtgb by omishgurl18 June 6, 2010 0 0 Get merch Get the wtgb mug. Buy Now — $32.95 See more merch