means true to the plumbline, but is generally used to express that self-possession which arises from perfect self-confidence. We also talk of a dancer's aplomb, meaning that he is a perfect master of his art.
(French. à plomb.)
“Here exists the best stock in the world men of aplomb and reserve, of great range and many moods, of strong instincts, yet apt for culture.” —Emerson: English Traits, p. 130.
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
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