Innocent, ingenuous (5)
I believe the answer is:
naive
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">innocent</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">ingenuous</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ ></span>
(Other definitions for naive that I've seen before include "Excessively trusting or innocent" , "Short on experience" , "Lacking sophistication" , "Innocent or not worldly enough" , "Ingenuous, easily deceived" .)