in full control of your faculties; "the witness remained collected throughout the cross-examination"; "perfectly poised and sure of himself"; "more self-contained and more dependable than many of the early frontiersmen"; "strong and self-possessed in the face of trouble"
Someone who is self-possessed is calm and confident and in control of their emotions. She is clearly the most articulate and self-possessed member of her family. = self-assured. calm, confident, and in control of your feelings, even in difficult or unexpected situations - used to show approval