Can be used, when said in a posh British accent, as a synonym for extremely drunk. The posh British accent concept can also be applied to virtually any noun, just add an 'ed' on the end.
1) A state of being where confidence wildly exceeds preparation—often accompanied by finger guns, questionable winks, and a playlist that’s way too sexy for the situation.
2) A cuckold in a dress.
This person is being a real Galebert.
The raid was lined upto kill C'thun, but one person was being a Galebert and cast a spell, at it promptly wiped the raid.