Internal (5)
I believe the answer is:
inner
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">internal</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that internal can be written as inner)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for inner that I've seen before include "Close to the centre; mental" , "(Of thoughts) intimate - (of circles) privileged" , "Internal - mental" , "closer than magpie" , "Not a bad shot" .)