fas, indecl. n. [root fa-, cf. for; Gr. φημί, φάναι]
I Orig. belonging to the relig. lang., the dictates of religion , divine law; opp. to jus, or human law (rare; cf. also: aequitas, justitia): jus ac fas omne delere, Cic. Att. 1, 16, 6; cf.: festis quaedam exercere diebus Fas et jura sinunt, Verg. G. 1, 269: contra fas, contra auspicia, contra omnes divinas atque humanas religiones, Cic. Verr. 2, 5, 13, § 34.—Personified: audi Juppiter, audite Fines, audiat Fas, Liv. 1, 32, 6: prima deum Fas quae Themis est Graiis, Aus. Technop. Idyll. 12: Fas omne mundi, i. e. the gods , Sen. Herc. Fur. 658.—
II Transf.
A A court-day , i. q. fastus (ante-class.): dies qui vocatur sic: QVANDO REX COMITIAVIT, FAS, Varr. L. L. 6, §§ 31, 32.—
B In gen. ( justice , equity , but usu. to be translated as an adjective), right , proper , allowable , lawful , fit , permitted; hence, possible (the predominant meaning of the word in prose and poetry; esp. freq. in the phrase fas est, with a subject-clause): fas, justum, pium, aequum subjici possunt honestati, Quint. 3, 8, 26: cum fas atque nefas exiguo fine libidinum Discernunt avidi, Hor. C. 1, 18, 10; Ov. M. 6, 585; cf.: quippe ubi fas versum atque nefas, Verg. G. 1, 505; Hor. Epod. 5, 87: jusque fasque est, Plaut. Cist. 1, 1, 22: si jus, si fas est, Ter. Hec. 387: sicut fas jusque est, Liv. 7, 31, 3: ut eum nihil delectaret, quod aut per naturam fas esset aut per leges liceret, Cic. Mil. 16, 43; cf.: quoad fas esset, quoad liceret, id. Agr. 2, 7, 19; and: huic legi nec obrogari fas est, neque derogari ex hac aliquid licet, id. Rep. 3, 22: si me fas est orare etiam abs te, pater, etc., Plaut. Bacch. 4, 9, 102: quid non adeptus est, quod homini fas esset optare? Cic. Lael. 3, 11: si eos hoc nomine appellari fas est, id. Mur. 37, 80: non esse fas, Germanos superare, si, etc., Caes. B. G. 1, 50 fin. : neque fas esse existimant, ea litteris mandare, id. ib. 6, 14, 3: ad quos (libellos) interim respicere fas sit, Quint. 10, 7, 31: velut si aliter facere fas non sit, id. 2, 13, 1; 8, 3, 36; 10, 2, 9; 12, 7, 1: nec scire fas est omnia, Hor. C. 4, 4, 22: fas omne est, Cytherea, meis te fidere regnis, there is every reason , Verg. A. 5, 800: si hoc fas est dictu, Cic. Tusc. 5, 13, 38: neque id me facere fas existimo, Plaut. As. 3, 1, 11: fas habere, id. Trin. 2, 2, 11; Quint. 3, 8, 13; Tac. A. 14, 30; id. G. 9: leporem et gallinam et anserem gustare fas non putant, Caes. B. G. 5, 12, 6; 6, 23 fin. : fas prohibet, etc., Ov. Tr. 2, 205: contra quam fas erat, Cic. Clu. 5, 12: ridetque (deus), si mortalis ultra Fas trepidat, Hor. C. 3, 29, 32: fas omne abrumpit, every right , obligation , Verg. A. 3, 55: exuere, Tac. H. 3, 5: et foedera respicere, id. ib. 4, 67; cf.: hostium quoque jus et sacra legationis et fas gentium rupistis, the law of nations , id. A. 1, 42; so in Tac. freq. = jus: patriae, the right , claim of one's native land , id. ib. 2, 10: armorum, id. H. 4, 58: disciplinae, id. A. 1, 19 al.