[let loose] {v.}
1a. or [set loose] or [turn loose] To set free; loosen or give up your hold on.
* /The farmer opened the gate and let the bull loose in the pasture./* /They turned the balloon loose to let it rise in the air./
1b. or [turn loose] To give freedom (to someone) to do something; to allow (someone) to do what he wants.
* /Mother let Jim loose on the apple pie./* /The children were turned loose in the toy store to pick the toys they wanted./
1c. To stop holding something; loosen your hold.
* /Jim caught Ruth's arm and would not let loose./
Compare: LET GO, LET OUT. 2a. {informal} To let or make (something) move fast or hard; release.
* /The fielder let loose a long throw to home plate after catching the ball./
2b. {informal} To release something held.
* /Those dark clouds are going to let loose any minute./
Syn.: CUT LOOSE, LET GO. 3. {informal} To speak or act freely; disregard ordinary limits.
* /The teacher told Jim that some day she was going to let loose and tell him what she thought of him./* /Mother let loose on her shopping trip today and bought things for all of us./
Syn.: CUT LOOSE, LET GO.