Tight-fitting undergarment (6)
I believe the answer is:
corset
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tight-fitting undergarment</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 corset that I've seen before include "Shaping undergarment" , "Tight-fitting ladies' garment" , "female garment!" , "fat controller?" , "Item of underwear" .)