Someone who is either an idiot, or spends too much
time taking drugs. Someone who shows signs of minimal
intelligence and/or
common sense.
This phrase can be used in an offensive or a friendly context.
"Look at that
prick, he's fuckin tuned to the moon, so he is"
"Ah've
goat my giro, ah'm gonna be
well tuned tae the moon the night so ah am"