Although saying in bocca al lupo to someone is basically the same as wishing them “good luck”, it is very important that you know that in Italy wishing good luck to someone by telling them “buona fortuna” is considered as being somehow impolite... No kidding! People will look you up and down as if you were wishing them bad luck.
The literal translation for in bocca al lupo would be “in the mouth of the wolf”. As for the etymology of this expression, various explanations have been advanced. One hypothesis has it that the idiom comes from the language of shepherds and farmers, who saw wolves as being a dangerous threat due to their voracious habit of preying on livestock.
An alternative theory traces back to the myth of the founding of Rome. The twin brothers Romulus and Remus were saved by a she-wolf that rescued them from the river Tiber by carrying them in her mouth.
Due to the apotropaic nature of this expression, you are not supposed to reply by saying “grazie” even though you know that you were actually wished good luck! Instead, you’ll be expected to say “crepi il lupo!”, which means “may the wolf die!” and finds its English equivalent in the expression “knock on wood!”.
Example:- In bocca al lupo per il tuo esame di oggi, Paola!
Crepi il lupo, Mamma!
- Break a leg in your exam today, Paola!
- Knock on wood, Mom!