Tenacity (11)
I believe the answer is:
persistence
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">tenacity</span>' is the definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for persistence that I've seen before include "Resolution" , "Dogged quality" , "grit" , "Tenacity" , "Refusal to accept refusal" .)