unpin
/ˌʌnˈpɪn/verb
(unpinned, unpinning)with obj.
1- unfasten or detach by removing a pin or pins取下别针（或钉）以解开。
1.1
- Chess release (a pinned piece or pawn), e.g. by moving away the piece it is shielding【棋】使摆脱牵制。