Powerful, mighty (6)
I believe the answer is:
strong
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">powerful</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(associated in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">mighty</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for strong that I've seen before include "Forceful" , "Potent" , "Resilient" , "Powerful; highly alcoholic" , "Able to withstand attack" .)