Hardy and sure-footed animal (3)
I believe the answer is:
ass
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">hardy and sure-footed animal</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 ass that I've seen before include "Silly fool or beast of burden" , "animal inside" , "Wally" , "Dolt" , "slow-witted person" .)