- a bomb.
- something or someone having a sudden and sensational effect: The news of his resignation was a bombshell.
- (esp formerly) a bomb or artillery shell
- a shocking or unwelcome surprisethe news of his death was a bombshell
- informal an attractive girl or woman (esp in the phrase blonde bombshell)
1708, from bomb (n.) + shell (n.). The figurative sense of “shattering or devastating thing or event” attested from 1860. In reference to a pretty woman (especially a blonde) it is attested from 1942 (“Bombshell” as title of a movie starring blond U.S. actress Jean Harlow (1911-1937) is from 1933).
see drop a bombshell.