Temerity, Rashness. These words are closely allied in sense, but have a slight difference in their use and application. Temerity is latin, and rashness is Anglo-saxon. As in many such cases, the Latin term is more select and dignified; the Anglo-Saxon more familiar and energetic. We show temerity in hasty decisions, and the conduct to which they lead. We show rashness in particular actions, as dictated by sudden impulse. It is an exhibition of temerity to approach the verge of a precipice; it is an act of rashness to jump into a river without being able to swim. Temerity, then, is an unreasonable contempt of danger; rashness is a rushing into danger from thoughtlessness or excited feeling. It is notorious temerity to pass sentence upon grounds uncapable of evidence. (barrow) Her rush hand in evil hour forth reaching to the fruit, she plucked, she eat. (milton)
Synonym: Rashness, precipitancy, heedlessness, venturesomeness.
Origin: L. Temeritas, from temere by chance, rashly; perhaps akin to Skr. Tamas darkness: cf. F. Temerite.