Badger; horse (3)
I believe the answer is:
nag
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">badger</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">horse</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(term for an old horse)</span><br/ ><br/ ></span>
(Other definitions for nag that I've seen before include "Scold like an old horse" , "Equine" , "Complain to or badger incessantly" , "Keep worrying" , "Badger continually like old horse" .)