Spine (8)
I believe the answer is:
backbone
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">spine</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for backbone that I've seen before include "Spine or courage" , "Fortitude - protection for the spinal cord" , "Lt protects the spinal cord" , "Informal courage of spinal kind" , "Strength of character" .)