Self-possession (9)
I believe the answer is:
composure
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">self-possession</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for composure that I've seen before include "Coolness" , "Self-possession" , "tranquillity" , "Calm state" , "Calmness and self-control" .)