Light-hearted (7)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">light-hearted</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for playful that I've seen before include "Frolicsome" , "Teasing, unserious" , "Frisky" , "Full of fun" , "Fun-loving" .)
(Other definitions for thaw that I've seen before include "spring weather?" , "Melt in heat" , "John, once regularly on TV" , "the end of a white Christmas?" , "(Of ice/snow) melt" .)