biggun noun anything big UK,1971 A shortening of “big one”; either deliberately jocular or matter-of-factly.
— Ivor Biggun, TheWinker’sSong(Misprint), 1978
It was one thing giving it the biggun up north but we had the best mob in the country[.] — Martin King and Martin Knight, TheNaughtyNineties, p. 46, 1999