'Unpin' definitions:

Definition of 'unpin'

(from WordNet)
verb
Remove the pins from; unfasten the pins of [ant: pin]

Definition of 'Unpin'

From: GCIDE
  • Unpin \Un*pin"\, v. t. [1st pref. un- + pin.] To loose from pins; to remove the pins from; to unfasten; as, to unpin a frock; to unpin a frame. [1913 Webster]