Closest to the centre (9)
I believe the answer is:
innermost
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">closest to the centre</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for innermost that I've seen before include "extremely intimate" , "Sort of secrets" , "Closest to the centre" , "Private" , "Who may have gone deepest" .)