Wartime partner (4)
I believe the answer is:
ally
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">wartime partner</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 ally that I've seen before include "Colleague, confederate" , "State formally cooperating with another" , "Friend in time of need" , "Join forces with" , "Co-operating person or nation" .)