self-possession
nounEtymology From self- + possession.
1
Idiomatic A confidence in one's own powers.
2
Idiomatic Calmness and composure, especially when under stress.
- She had a very fresh complexion and a pretty, round little face saved from any dolliness by the steadiness of her blue eyes, the firmness of her mouth, and the expression of quiet self-possession.2022, J. Storer Clouston, The Adventures of M. D'Haricot: