v. t. [ 1st pref. un- + turn. ] To turn in a reserve way, especially so as to open something;
a. [ Pref. un- + turned. ] Not turned; not revolved or reversed. [ 1913 Webster ]
To leave no stone unturned,
[ He ] left unturned no stone
To make my guilt appear, and hide his own. Dryden. [ 1913 Webster ]