Characteristic feature (5)
I believe the answer is:
trait
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">characteristic feature</span>' is the definition.<br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for trait that I've seen before include "Mannerism" , "Distinguishing feature" , "Quirk" , "Habit" , "A characteristic of straitened kind" .)