Recover strength (5)
I believe the answer is:
rally
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">recover strength</span>' is the definition.<br/ ><span class="explanation-format__explanation">(to rally is to recover one's health)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for rally that I've seen before include "Regain one's strength" , "Recuperate in gathering" , "(Of shares) increase after a fall" , "Get better; car meet" , "Mass meeting -- revive" .)