close ranks

Từ điển Oxford Advanced Learner 8th

close ˈranks idiom
1. if a group of people close ranks, they work closely together to defend themselves, especially when they are being criticized
•It's not unusual for the police to close ranks when one of their officers is being investigated.
2. if soldiers close ranks, they move closer together in order to defend themselves
Main entry: ↑close_idiom