Synonyms of self-possessed in English:

self-possessed


See US English definition of self-possessed

See UK English definition of self-possessed

adjective

1‘a self-possessed young architect’

SYNONYMS
assured, self-assured, calm, cool, cool, calm, and collected, composed, at ease, tranquil, serene, unperturbed, unruffled, impassive, nonchalant, confident, self-confident, sure of oneself, poised, dignified, equable, imperturbable, suave, urbane, elegant
informal together, unfazed, unflappable
North American informal nonplussed
rare equanimous
ANTONYMS

unsure, nervous