Fleet of warships (6)
I believe the answer is:
armada
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fleet of warships</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for armada that I've seen before include "lot of craft" , "Many ships" , "group of ships" , "A great fleet - Spain had one" , "The Spanish force" .)