Lady's private room
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">lady's private room</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 boudoir that I've seen before include "Woman's private room" , "Milady's chamber" , "Lady's private room" , "Private sitting room" , "Lady's bedroom" .)