mean business
US /miːn ˈbɪz.nɪs/
UK /miːn ˈbɪz.nɪs/

1.
falar sério, estar determinado
to be serious and determined about what one is doing or saying
:
•
When the boss walked in with that look on his face, we knew he meant business.
Quando o chefe entrou com aquela expressão, sabíamos que ele falava sério.
•
The new security measures show that the company means business about protecting its data.
As novas medidas de segurança mostram que a empresa fala sério sobre a proteção de seus dados.