The French expression tout à coup (pronounced too ta koo) means "all of a sudden." It literally translates to "all at (a) blow." Its register is normal. Tout à coup is a very common French expression which indicates that something happened abruptly and unexpectedly.
- Sans dire un mot, elle a tout à coup pris son sac et est partie.
- Without a word, she suddenly picked up her bag and left.
- Tout à coup, j'ai perdu l'appétit.
- All of a sudden, I lost my appetite.
Tout à coup is often used interchangeably-though technically incorrectly-with the French expression tout d'un coup.