im·per·turb·a·ble
adjective/ˌɪmpəˈtɜːbəbl/
/ˌɪmpərˈtɜːrbəbl/
(formal)- not easily upset or worried by a difficult situation; calm
冷静的；不易生气的；沉着的 - Above all he was imperturbable and never upset when things appeared to go against him.
最重要的是，当事情似乎对他不利时，他镇定自若，从不沮丧。 - She faces challenges with imperturbable calm.
她以镇定自若的态度面对挑战。
Word Originlate Middle English: from late Latin imperturbabilis, from in- ‘not’ + perturbare (from per- ‘completely’ + turbare ‘disturb’). - Above all he was imperturbable and never upset when things appeared to go against him.