Military tribunal (5,7)
I believe the answer is:
court martial
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">military tribunal</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 court martial that I've seen before include "Try, in service" , "Soldiers tried here" , "Military justice" , "Military trial" , "Decider on military law" .)