A clandestine item or mode of attack unknown to the enemy. The term came into wide use during World War II, when it was rumored that Hitler was going to launch a powerful secret weapon against Great Britain. Subsequently the term was applied to pilotless planes, robot bombs, rockets, and nuclear bombs. Thereafter it entered the civilian vocabulary, where it is used in sports (“Bill’s second serve, stronger than the first, is his secret weapon”) and numerous other activities. Edith Simon had it in The Past Masters (1953): “See the candid camera at work, that misnamed secret weapon.”