Martial (8)
(Other definitions for arts that I've seen before include "'Poetry, music, painting (4)'" , "Drawing, painting, etc" , "Products of human creativity" , "they may be performing" , "Humanities" .)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">martial</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for military that I've seen before include "Relating to the army" , "Relating to armed forces" , "Of soldiers and warfare" , "in the field" , "Related to soldiering" .)