coo coo clock Share definition Flag Someone that has totally gone crazy and lost it. They have an embarrassing temper that makes you laugh at them. What are you a coo coo clock? Ok coo coo clock! Control yourself don't be a coo coo clock! coo coo clock by Rat Tail January 11, 2006 0 0 Get merch Get the coo coo clock mug. Buy Now — $32.95 See more merch