self-possessed /ˌsɛlfpəˈzɛst/ adjective Learner's definition of SELF-POSSESSED
[more self-possessed; most self-possessed]
: having or showing control of your feelings or actions especially in a difficult situation沉着镇静的;镇定的 — self-possession
/ˌsɛlfpəˈzɛʃən/ noun [noncount]