yawnsense Share definition Flag The incredibly stupid things you say when you are overly tired. At around 1 am, Stephanie started telling knock-knock jokes and giggling. Mark told her she was talking yawnsense. yawnsense by kcitsleipztirf November 5, 2010 0 0 Get merch Get the yawnsense mug. Buy Now — $32.95 See more merch