Word of the Day: Temerity (noun)
Definition: Recklessness, foolhardy disregard for danger.
Usage: The adjective, "temerous," is now rarely used but still grammatically kosher. The verb, "temerate," is completely obsolete and probably beyond redemption. The sense of today's word, the noun, is diametrically opposed to "timidity" despite the similarity in sound, so apply it judiciously.
Suggested Usage: Today's word does not just mean "daring" but "reckless if not dangerously daring: "Serena, the temerity to pump gas while smoking a cigarette does not impress me." The danger may lurk in any quarter, "Claude showed remarkable temerity in asking for a raise in the midst of a round of managerial lay-offs."
Etymology: From Latin temeritas "rashness, temerity," from temere "blindly, recklessly." The underlying PIE root, *temes- "dark," also produced Latin tenebrae "darkness," Sanskrit tamas "darkness," Lithuanian tamsus "dark," and Russian tëmny "dark."
—Dr. Language, yourDictionary.com