1. to make rules, restrictions, or supervision more strict or rigorous; to increase oversight or regulation
The government decided to tighten control over financial institutions after the scandal.
O governo decidiu apertar o controle sobre instituições financeiras após o escândalo.
2. to exert greater authority or power over someone or something
The manager began to tighten control over the department's budget.
O gerente começou a apertar o controle sobre o orçamento do departamento.