Word of the Day:

: marked by extreme calm, impassivity, and steadiness : serene

The imperturbable pilot did not panic when her plane flew into an electrical storm.

"But ZZ Top has always excelled when it lets notes growl and grooves simmer, relaxing rather than rushing, and maintaining a laid-back musical cool to parallel its imperturbable attitude." - From a review by Bob Gendron in the Chicago Tribune, October 12, 2012

More example sentences

There is an interesting time lag between the appearance of "imperturbable" and its antonym, "perturbable." Although "imperturbable" is known to have existed since the middle of the 15th century, "perturbable" didn't show up in written English until 1800. The verb "perturb" (meaning "to disquiet" or "to throw into confusion") predates both "imperturbable" and "perturbable"; it has been part of English since the 14th century. All three words derive from Latin "perturbare" (also meaning "to throw into confusion"), which in turn comes from the combination of "per-" and "turbare," which means "to disturb." Other relatives of "imperturbable" include "disturb" and "turbid."