Reserved, laconic (8)
I believe the answer is:
taciturn
<span class="explanation-format__ClueExplanation">This clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">reserved</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >'<span class="explanation-format__original">laconic</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ ></span>
(Other definitions for taciturn that I've seen before include "Aloof" , "Untalkative" , "Quiet and uncommunicative" , "Disinclined towards conversation" , "Reserved, saying little" .)