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

1.
bersungguh-sungguh, serius
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.
Apabila bos masuk dengan riak wajah itu, kami tahu dia bersungguh-sungguh.
•
The new security measures show that the company means business about protecting its data.
Langkah-langkah keselamatan baharu menunjukkan bahawa syarikat bersungguh-sungguh dalam melindungi datanya.