Great power or strength (5)
I believe the answer is:
might
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">great power</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">strength</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(might is a kind of strength)</span><br/ ><br/ ></span>
(Other definitions for might that I've seen before include "What functions as an auxiliary" , "Clout" , "Powerfulness" , "- - and main" , "Great power, strength" .)