McGugan Posted in M Best definition McGugan Comes from the gangster Mike McGugan. He was a l33t scripter, and the leader of the McGugamafia. Meaning nothing but cool. “Mike McGugan runs your shit homie” How satisfied are you with the definition? Looking for McGugan meaning? Delighted that you discovered the greatest determine on our web site! Recently this definition was actually observed 32 times.