Dexterity, adeptness (8)
I believe the answer is:
deftness
<span class="explanation-format__ClueExplanation">I believe this clue is a double definition.<br/ ><br/ >'<span class="explanation-format__original">dexterity</span>' is the first definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >'<span class="explanation-format__original">adeptness</span>' is the second definition.<br/ ><span class="explanation-format__explanation">(I know that adeptness can be written as deftness)</span><br/ ><br/ ></span>
(Other definitions for deftness that I've seen before include "Skill" , "Dexterity of movement" .)