1. Conduct or behavior that appears questionable, illicit, or potentially criminal in nature
The police reported suspicious activity in the neighborhood last night.
A polícia relatou atividade suspeita no bairro na noite passada.
2. Actions that warrant investigation or closer scrutiny by authorities
Banks must report suspicious activity to financial regulators.
Os bancos devem relatar atividade suspeita aos órgãos reguladores financeiros.