let somebody loose

Từ điển Oxford Advanced Learner 8th

let sb/sth ˈloose idiom
1. to free sb/sth from whatever holds them/it in place
•She let her hair loose and it fell around her shoulders.
•Who's let the dog loose?
2. to give sb complete freedom to do what they want in a place or situation
•He was at last let loose in the kitchen.
•A team of professionals were let loose on the project.
Main entry: ↑loose_idiom