aplomb

noun

1. (uncountable, usually)Self-confidence; poise; composure.

   “His nonchalance and aplomb during hard times have always been his best character trait.”

   ““Oh, Wooster,” he said, “I was talking to my mother a night or two ago.” “Oh, yes?” I said, with a slight wave of the hand intended to indicate that if he liked to talk to his mother anywhere, all over the house, he had my approval. “She tells me you are interested in mice.” I didn't like the trend the conversation was taking, but I preserved my aplomb. “Why, yes, fairly interested.” “She says she found you trying to catch one in my bedroom!””

   “We can handle functions of a few variables with some aplomb and view sets of quantities totalling IO6 or IO7 with sangfroid.”

   “They have a seven-year-old son named Timothy, never called Timmy or Tim; a little scrawny guy who wears thick glasses already, and who tucks his striped T-shirts into his pants with the aplomb of a silver-templed CEO.”

   “Fly-half Jonny Wilkinson put his below-par performance against Argentina behind him with a fine first-half showing, slotting four kicks from six and controlling his back-line with aplomb, while England's three-quarters were brimming with life and clinical with their execution.”

2. (uncountable, usually)The apparent elegance and precision exhibited by a confident, accomplished dancer.
3. (uncountable, usually)The perpendicular; perpendicularity.