Active, full of energy (7)
I believe the answer is:
dynamic
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">active</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">full of energy</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ ></span>
(Other definitions for dynamic that I've seen before include "I'm Candy (anag) - full of beans" , "Full of energy and ideas" , "Driving" , "Constantly changing" , "Powerful and vigorous" .)