aplomb
definition
self-confidence or assurance, especially in a demanding situation
example
Despite the unexpected questions from the audience, she handled the entire presentation with aplomb, impressing everyone with her poise and clarity.
synonyms
poiseassuranceconfidence
word origin — late 19th century, from French 'aplomb', which means 'perpendicularity', derived from 'plomber', meaning 'to plumb'.