Waist measurement (5)
I believe the answer is:
girth
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">waist measurement</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 girth that I've seen before include "Circumferential measure" , "Right (anag.)" , "Distance round a body" , "Size of waist perhaps" , "A band passing under horse's belly" .)