Acronym for Great Unlucky One. Originally based on a D&D character who spent his entire existence being either breathed on or sat on by dragons - is now used as an invisible scapegoat for any and all spurts of bad luck. Example: Four finals in one day? Looks like the G.U.O. strikes again!
G.U.O.
Meaning of G.U.O. in English
Slang English vocab. Английский сленговый словарь. 2012