Castle protectors (5)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">castle protectors</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for moats that I've seen before include "Water defences" , "Defensive water-filled ditches" , "Trenches around castles" , "Castle ditches" , "Fortifications filled with water" .)