: to allow (someone or something) to move or go freely
He let the dogs loose in the courtyard.
cattle let loose to graze on the green fields
—often used figuratively
a director who's willing to let her actors loose to interpret their roles however they see fithow to stop the violence that has been let loose on the city
2
: to produce (something, such as a cry) in a sudden and forceful way
The crowd let loose an enormous groan when the pass was intercepted.