Kittenish, playful (6)
I believe the answer is:
frisky
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">kittenish</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I know that kittenish can be written as frisky)</span><br/ ><br/ >'<span class="explanation-format__original">playful</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ ></span>
(Other definitions for frisky that I've seen before include "Playful, full of energy" , "Animated" , "High-spirited" , "Lively like playful dog" , "In high spirits" .)