Musing (10)
I believe the answer is:
reflection
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">musing</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I know that musing can be written as reflection)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for reflection that I've seen before include "Effect of not absorbing light" , "Mirror image" , "serious thought?" , "mental study's required" .)