umop apisdn Share definition Flag = "Upside down.": Read Upside down, and backwards. Try using Ctrl+Alt+Arrow-Down Do you know Jack Johnson? He wrote this song: "umop apisdn". umop apisdn by MopfMore April 2, 2015 0 0 Get merch Get the umop apisdn mug. Buy Now — $32.95 See more merch