Poise, self-possession (6)
I believe the answer is:
aplomb
This clue is a double definition.
'poise' is the first definition.
(synonyms)
'self-possession' is the second definition.
(synonyms)
(Other definitions for aplomb that I've seen before include "Cool self-confidence" , "Self-possession, assurance" , "Self-satisfied dignity and confidence" , "Self confidence" , "Dignified self-confidence" .)