Restraining garment (12)
I believe the answer is:
straitjacket
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">restraining garment</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 straitjacket that I've seen before include "Garment used to restrain people" , "restraint" , "restriction" , "Restraining garment" .)