Sinew (6)
I believe the answer is:
tendon
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">sinew</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for tendon that I've seen before include "Strong tissue cord connecting muscles" , "Strong band of tissue connecting muscles" , "Fibrous tissue attaching muscle to bone" , "Fibrous band" , "Strong tissue that connects muscle" .)