an iron fist
US /æn ˈaɪərn fɪst/
UK /æn ˈaɪərn fɪst/

1.
mão de ferro, com rigor
to rule or control with strict and often harsh authority
:
•
The dictator ruled his country with an iron fist.
O ditador governou seu país com mão de ferro.
•
She manages her team with an iron fist, ensuring everyone follows the rules.
Ela gerencia sua equipe com mão de ferro, garantindo que todos sigam as regras.