Wiktionary
unflustered
a. Not flustered; calm
WordNet
unflustered
adj. free from emotional agitation or nervous tension; "the waiters were unflurried and good natured"; "with contented mind and unruffled spirit"- Anthony Trollope [syn: unflurried, unperturbed, unruffled]
Usage examples of "unflustered".
Charlie Lomas managed to repeat his unflustered performance at the committal, impressing the jury with his open manner and his obvious unhappiness about the disappearance of his cousin.