1. to not be drunk or intoxicated; to have a clear mind free from the effects of alcohol or drugs
After drinking all night, he needed to be sober before driving home.
Depois de beber a noite toda, ele precisava estar sóbrio antes de dirigir para casa.
2. to be serious, thoughtful, or not affected by emotion; to have a calm and measured demeanor
We need to be sober in our judgment about this serious matter.
Precisamos estar sóbrios em nosso julgamento sobre este assunto grave.