Is it ensure, insure, or assure?
1540s, "to strike hard with a loud blow," from a Scandinavian sourse akin to Old Norse banga "to pound, hammer" of echoic origin. Slang meaning "have sexual intercourse with" first recorded 1937. Bang-up "excellent, first-rate," 1820, probably shortened from phrase bang up to the mark. The noun is recorded from late 16c.
This is the way the world ends
Not with a bang but a whimper
[T.S. Eliot, "Hollow Men," 1925]
Bang (bāng, bäng), Bernhard Lauritz Frederik. 1848-1932.
Danish veterinarian who discovered Brucella abortus, the agent of brucellosis in cattle and of undulant fever in humans.
Precisely; exactly: bang on the hour (1820s+)noun
[late 1980s+ Los Angeles gangs; from the rhyme, but influenced by gang bang, ''serial sex act done by a group of males to one woman'']