1. A day characterized by misfortune, bad luck, or negative events that affects someone specifically
That was a terrible day for you, losing your wallet and missing your flight.
Um dia péssimo para você, perder sua carteira e perder seu voo.
2. An expression of sympathy or acknowledgment of someone's difficult day
I heard about your accident. What a terrible day for you!
Ouvi falar do seu acidente. Que dia péssimo para você!