Entry 1 sense Webster, 1913 Unleash /ən-lēsh'/ · Un·leash · IPA /ʌnˈliʃ/ 01 v. t. To free from a leash, or as from a leash; to let go; to release; as, to unleash dogs. 1. To free from a leash, or as from a leash; to let go; to release; as, to unleash dogs.