Military action (6)
(Other definitions for combat that I've seen before include "type of jacket" , "Fight or contest, may be mortal" , "Oppose" , "A fight or contest, sometimes mortal" , "Fight - strive against" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">military action</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that battle is a type of military action)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for battle that I've seen before include "Struggle tenaciously" , "war" , "Lengthy fight" , "Encounter" , "Armed conflict" .)