Siege engine (9)
I believe the answer is:
trebuchet
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">siege engine</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for trebuchet that I've seen before include "Old weapon" , "Medieval engine of war" , "Medieval siege engine" , "onager?" , "Old slinger" .)