A red headed person who is simply an idiot.
“You heard of that new show?”
“Yeah it was cool, but the Red Red ruined it.”
“Yeah.”
Red-Over-Red in navigational aids is the display of two Red lights in a vertical line, visible at night which means the Captain is dead. Vessel not under command, no Commanding Officer.
When you are not under the command of anyone you are Red-Over-Red!