Unsure (8)
I believe the answer is:
insecure
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">unsure</span>' is the definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for insecure that I've seen before include "Sinecure for those lacking in confidence" , "exposed to danger" , "uncertain" , "Wavering" , "Lacking self-confidence or assurance" .)