Covert, secret (11)
I believe the answer is:
clandestine
<span class="explanation-format__ClueExplanation">I believe this is a double definition.<br/ ><br/ >'<span class="explanation-format__original">covert</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">secret</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that secret can be written as clandestine)</span><br/ ><br/ ></span>
(Other definitions for clandestine that I've seen before include "backroom" , "Done secretly" , "Undercover" , "Private" , "Secret" .)