1. A curse or wish for someone to experience a day filled with misfortune, problems, or negative events
I hope you have a bad day for what you did to me.
Espero que tenha um dia ruim pelo que você me fez.
2. An expression of anger, resentment, or revenge towards someone
After he insulted her, she muttered 'have a bad day' under her breath.
Depois que ele a insultou, ela murmurou 'que tenha um dia ruim' baixo.