Taciturn, reserved (8)
I believe the answer is:
reticent
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">taciturn</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(similar in meaning)</span><br/ ><br/ >'<span class="explanation-format__original">reserved</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(synonyms)</span><br/ ><br/ ></span>
(Other definitions for reticent that I've seen before include "Secretive" , "Reserved, retiring" , "Uncommunicative" , "Not wanting to talk" , "Reserved, loath to talk" .)