temerity Look up temerity at Dictionary.com
early 15c., from M.Fr. témérité (15c.), from L. temeritatem (nom. temeritas) "blind chance, accident, rashness," from temere "by chance, blindly, casually, rashly," related to tenebrae "darkness," from PIE base *temes- "dark" (cf. Skt. tamas- "darkness," tamsrah "dark;" Avestan temah "darkness;" Lith. tamsa "darkness," tamsus "dark;" O.C.S. tima "darkness;" O.H.G. dinstar "dark;" O.Ir. temel "darkness").