Source : Webster's Revised Unabridged Dictionary (1913)

Unhitch \Un*hitch"\, v. t. [1 st pref. un- + hitch.]
   To free from being hitched, or as if from being hitched; to
   unfasten; to loose; as, to unhitch a horse, or a trace.

Source : WordNet®

unhitch
     v : unfasten or release from or as if from a hitch [ant: {hitch}]