Military engagement (6)
I believe the answer is:
battle
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">military engagement</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 battle that I've seen before include "Military engagement" , "Warfare" , "Skirmish" , "Lengthy conflict" , "Fight between opposing forces" .)