WHAMMY Meaning of WHAMMY in English ■ noun ( plural whammies ) informal1》 an event with a powerful and unpleasant effect; a blow. 2》 chiefly US an evil or unlucky influence.Origin1940s: from wham + -y 1 . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004