Royal household officer (7)
I believe the answer is:
equerry
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">royal household officer</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 equerry that I've seen before include "Officer attendant upon British sovereign" , "Royal aide" , "Officer of the British royal household" , "Attendant of royalty" , "Attendant at court" .)