Don Quixote's horse (9)
I believe the answer is:
rosinante
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">don quixote's horse</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for rosinante that I've seen before include "Pathetic nag" , "Don Quixote's horse" .)