Constabulary (6)
I believe the answer is:
police
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">constabulary</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that constabulary can be written as police)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for police that I've seen before include "Limbs of the law" , "... custodians of law and order" , "Branch of the security forces" , "Boys in blue" , "Lawmen" .)