Clear, transparent (6)
I believe the answer is:
limpid
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">clear</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">transparent</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for limpid that I've seen before include "Crystal clear, transparent" , "Crystal-clear" , "Completely clear" , "Calm" , "Translucent" .)