Alternatively, it means to fire somebody from a job.
Basically, the word describes any situation in which someone's position or status is completely stripped away from them in one fell swoop.
This phrase derives from the book and TV series, Game of Thrones, in which there is a castle on a high mountain with a hatch built into the floor. This hatch is called the "Moon Door." When opened, the Moon Door releases people into mid air, so that they fall directly to the floor of the Vale far below.
N, A nickname given to any person named Amanda. A MoonDoo must be sassy, sweet, smart and funny. There are no physical requirements set to become a MoonDoo. Sexual orientation, race and religion do not limit the powers or obligations that come with the title of MoonDoo. All potential MoonDoos must be given the nickname by a close friend and they can not nominate themselves into MoonDooship. To be a MoonDoo, one MUST MUST MUST have a big heart.
"How's it going MoonDoo?"
"...and then MoonDoo told her to forcibly insert the lifelineexercise into her anus!"