From Longman Dictionary of Contemporary Englishunflappableun‧flap‧pa‧ble /ʌnˈflæpəbəl/ adjective informal CALMhaving the ability to stay calm and not become upset, even in difficult situations
Examples from the Corpus
unflappable• A good radio-host must be unflappable.• He called home often at first for hour-long talks with Maude, whose faith in him was unflappable.• Hogan was a smooth, confident Foreign Office man, unflappable and oozing with reasonableness.• Like Plum, she was unflappable and smart, but both her role and her manner were different from his.• She writes casually, with unflappable assurance.• But the quiet, efficient and unflappable Brett managed to instil more patience into his charge.• Many on Wall Street have therefore concluded that something panicked the usually unflappable chairman.• The Giants always said he had the stuff, the command, the unflappable nature of the very best pitchers.• Between numbers by the unflappable Ramblers, the stars are birthing new comedy duets. 