whammo

[ hwam-oh, wam-oh ]

/ ˈʰwæm oʊ, ˈwæm oʊ /

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.

wham.

Origin of whammo

First recorded in 1930–35; wham + -o