A state of total, irrevocable madness or delusion. Refers to the film "The Wizard of Oz", and Dorothy being in another world entirely unconnected from her reality.
Don't bother Garry over there. He's been over the rainbow ever since that bad acid trip.
This is a very deadly mental disorder that causes rainbowtardation which includes: Crying when someone hates rainbowX watching his videos every single day a lack of intelligence a lack of 0 grass touched and no father.
Who ever has this will defend anything thats said against rainbowX
RainbowX fan: AHAHAHHA RAINBOWX IS COOL POGGERS E BRUH
Random dude: oh shit god gave this man RainbowX Syndrome 1223
A "Grim Rainbow" is a term used to describe following a trail which leads to something ultimately pointless, dark, and oftentimes insulting. To follow a Grim Rainbow is to suffer humiliation, and defeat, many times over.
If you believe a Grim Rainbow, then you are suffering from a sad delusion.
"Dude, hearing that Brian Blessed died, only to discover it was a sick joke made me believe in a GrimRainbow"