1. A day marked by misfortune, bad luck, or a series of unfortunate events
Yesterday was a dia desafortunado - I lost my keys, missed my bus, and had an argument with my boss.
Ontem foi um dia desafortunado - perdi minhas chaves, perdi o ônibus e tive uma discussão com meu chefe.
2. A day when things go wrong or plans don't work out as intended
It turned out to be a dia desafortunado when the weather ruined our picnic plans.
Acabou sendo um dia desafortunado quando o tempo arruinou nossos planos de piquenique.