dies nefasti -- days unfit for public business

    nefāstus adj.    [nefas], contrary to religion, irreligious, impious: iniusta nefasta dicere,    XII Tabb. ap. C.—As subst n. (sc. crimen), a wicked deed, abomination, profanity: quid intactum nefasti Liquimus? H.—Of days, unhallowed, unpropitious, on which courts or public assemblies must not sit: ille (Numa) nefastos dies fastosque fecit, L.: (dies) per quem tria verba silentur (i. e. on which the praetor does not utter his words of authority: do, dico, addico), O.— Unlucky, inauspicious: Ille et nefasto te posuit die, etc., H.: ne terra victoriae suae, L.