aplomb

Từ điển American Heritage Dictionary 4th

a·plomb (ə-plŏmʹ, ə-plŭmʹ)n.
Self-confident assurance; poise. See Synonyms at confidence. [French, from Old French a plomb, perpendicularly : a, according to (from Latin ad-. See ad-) + plomb, lead weight (from Latin plumbum, lead).]

• Từ đồng nghĩa / Synonyms:
  assuredness, cool, poise, sang-froid