nĕfārĭus, a, um, adj. [nefas],
I impious, execrable, abominable, nefarious (class.; syn.: impius, sacrilegus): homo nefarius et impius, Cic. Off. 2, 14, 51: nefarius Atreus, Hor. A. P. 186: voluntates consceleratae ac nefariae, Cic. Sull. 9, 28: scelestum ac nefarium facinus, id. Rosc. Am. 13, 37: singularis et nefaria crudelitas, Caes. B. G. 7, 77; Cic. Rep. 3, 9, 14: multa commemorare nefaria in socios, id. Off. 2, 8, 28: nefario scelere se obstringere, Caes. B. C. 2, 32: nuptiae. Gai. Inst. 1, 64.—
II Subst.: nĕfārĭum , ii, n., a heinous act, a crime : rem publicam nefario obstringere. Liv. 9, 34.—Hence, adv.: nĕfārĭē , impiously, execrably, heinously, abominably : aliquid nefarie flagitioseque facere, Cic. Verr. 1, 13, 37; id. Div. in Caecil. 12, 38: nefarie moliri pestem patriae, id. Cat. 2, 1, 1: nefarie occisus pater, id. Rosc. Am. 11, 30.