It's closed for fighting (4)
I believe the answer is:
fist
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">it's closed for fighting</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for fist that I've seen before include "Hand with the fingers clenched in the palm" , "Hit with a clenched one" , "duke" , "handwriting?" , "One may deck in a ring" .)