Relating to the kidneys (5)
I believe the answer is:
renal
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">relating to the kidneys</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for renal that I've seen before include "Referring to organ" , "Pertaining to the kidney" , "Concerning the kidneys" , "Concerned with organ" , "like kidneys" .)