Vigour, zip (6)
I believe the answer is:
energy
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">vigour</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that vigour can be written as energy)</span><br/ ><br/ >'<span class="explanation-format__original">zip</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that zip can be written as energy)</span><br/ ><br/ ></span>
(Other definitions for energy that I've seen before include "Seventeen forty six defeat for Bonnie Prince Charlie" , "Vigour, vim, vitality" , "Vitality, power" , "Healthy capacity for vigorous activity" , "Strength, vitality" .)