let loose something

US /lɛt luːs ˈsʌmˌθɪŋ/
UK /lɛt luːs ˈsʌmˌθɪŋ/
"let loose something" picture
1.

to release something, often with force or without restraint

:
The dog was let loose in the park to run freely.
He let loose a string of curses after hitting his thumb.