JMIU Share definition Flag Just Made It Up. There's a silent and invisible 'A' at the end. That 'A' is for arsehole. "Hey, here's a statistic that is completely flawed but i'm gonna base a million dollar project around it". "Cool, where's it from?" "JMIU" JMIU by antomatic May 20, 2014 0 0 Get merch Get the JMIU mug. Buy Now — $32.95 See more merch