/ ˈbɒmʃel; NAmE ˈbɑːm-/ noun [ usually sing. ] ( informal )
1.
an event or a piece of news which is unexpected and usually unpleasant :
The news of his death came as a bombshell.
She dropped a bombshell at the meeting and announced that she was leaving.
2.
a blond(e) bombshell a very attractive woman with blonde hair