Englishimperturbable
adjective
my father was a solid, imperturbable man:
self-possessed, composed, collected, calm, cool, calm, and collected, as cool as a cucumber, coolheaded, self-controlled, poised, tranquil, serene, relaxed, easygoing, unexcitable, even-tempered, placid, sedate, phlegmatic;
unperturbed, unflustered, untroubled, unbothered, unruffled, undismayed, unagitated, undisturbed, unmoved, nonchalant, at ease;
informal unflappable, unfazed, together, laid-back;
North American, informal nonplussed;
rare equanimous.
▷antonyms edgy; excitable.