Leaderless (5)
I believe the answer is:
unled
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">leaderless</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 unled that I've seen before include "Not shown the way" , "Without someone in charge" .)