Semi-Somnia Share definition Flag The inability to go to sleep until 3 or 4 in the morning, no matter how tired you are. I would've gotten to bed earlier, but I suffer from semi-somnia. I couldn't fall asleep until 3. Semi-Somnia by Bloe Jackman June 8, 2010 0 0 Get merch Get the Semi-Somnia mug. Buy Now — $32.95 See more merch