Resilience (7)
I believe the answer is:
stamina
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">resilience</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for stamina that I've seen before include "bottom" , "Resilience" , "grit" , "Vigour" , "capacity to endure" .)