wham•moPronunciation: (hwam'ō, wam'ō), [key] Informal.
(used to indicate the sound of a blow, collision, falling object, etc.).
immense energy; vigor: a movie with plenty of whammo to please the kids.
characterized by such a strong effect: a show with a whammo ending.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.