An arm or a leg (4)
I believe the answer is:
limb
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">an arm</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">a leg</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for limb that I've seen before include "Human's extension" , "Arm, leg or wing" , "as part of plane, say" , "Eg wing" , "Bough" .)