An oxymoronic term used to describe something intolerably rubbish. Stems from the British slang 'Balls', as in, 'That's just balls' and the slang 'Gash', as in, 'That's just gash'.
Mark just bought a new car, but it's f***ing ballsgash. It only cost him a tenner.
by TheWittySoldier July 10, 2009