Marine leader? (5)
I believe the answer is:
ultra
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">marine leader?</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 ultra that I've seen before include "Prefix meaning beyond or extremely" , "Extreme (as in UV)" , "Above, beyond, super" , "Extreme - extremist" , "Violet's predecessor" .)