纵虎归山

纵虎归山 [zòng hǔ guī shān]

1. ■ let the tiger return to the mountain --to breed [cause] calamity for the future; To let one's enemy go unharmed is to have a potential danger lurking somewhere which would prove menacing to life one of these days.; set a tiger free -- to tolerate the wicked acts of evildoers