Self-possession is calm control of yourself when things are difficult. Answering the hostile question without your voice changing.
It is not the same as confidence. A confident person believes they will do well; a person with self-possession may be terrified and simply does not show it. The word turns up in descriptions of people under pressure — a witness who kept her self-possession, a boy with a self-possession beyond his years. The adjective self-possessed is commoner than the noun, and both are compliments. Losing your self-possession names the moment the mask slips.
1nounself-possessionCalm control of your feelings and behaviour under pressure.
“She answered the accusation with complete self-possession.”
Middle English
self
English
self
English, today
self-possession
From self- + possession. self comes from Middle English self. From Middle English salve, self, silf, from Old English self, seolf, sylf, from Proto-Germanic selbaz, from Proto-Indo-European selbʰ- (“one's own”). 2
Etymology from Wiktionary, CC BY-SA