let off the leash, let [sb] off the leash, let [sb] off his/her leashv exprverbal expression: Phrase with special meaning functioning as verb--for example, "put their heads together," "come to an end."
figurative (release [sb] from restraint, control) (比喻)
解开...的枷锁，解开...的束缚
解放 jiě fàng
When they saw that he could handle the job, they let him off his leash and he quickly moved up to a higher position.