n. A state of calm, unruffled self-assurance; aplomb, composure.
the GNU version of the Collaborative International Dictionary of English
n. The state or quality of being imperturbable.
The Century Dictionary and Cyclopedia
n. The condition or quality of being imperturbable.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. calm and unruffled self-assurance
Word Usage
"His imperturbability was a valuable asset; he never lost heart or dreamed of retiring from the arena, nor did he ever cease to impress his party as being their most useful and acceptable representative."