unfasten Meaning, Definition & Usage

  1. verb cause to become undone
    • unfasten your belt
  2. verb become undone or untied
    • The shoelaces unfastened

WordNet

Un*fas"ten transitive verb
Etymology
1st pref. un- + fasten.
Definitions
  1. To loose; to unfix; to unbind; to untie.

Webster 1913