1. to act or speak with prudence and circumspection, avoiding drawing attention or causing offense; to maintain confidentiality
Please be discreet about this matter; it's confidential.
Por favor, seja discreto sobre este assunto; é confidencial.
2. to behave carefully and tactfully in a sensitive situation
You should be discreet when discussing personal matters with colleagues.
Você deve ser discreto ao discutir assuntos pessoais com colegas.