Lewis & Short

sons, sontis, adj. (nom. sing., Fest. p. 297; Aus. Idyll. 12) [Part. from root as-, es-; Sanscr. as-mi; Gr. εὶμί; Lat. esum, sum; cf. Gr. ἐτεός, ἐτήτυμος; prop. he who was it, the real person, the guilty one].

  1. I. Guilty, criminal; subst., a guilty person, an offender, malefactor, criminal (freq. and class., esp. as subst.; syn.: reus, nocens): anima, Verg. A. 10, 854; Ov. M. 6, 618: ulni, id. ib. 7, 847: di, Stat. Th. 5, 610: manus foedata sanguine sonti (poet. for sontis), Ov. M. 13, 563: morae ab igne supremo, Stat. Th. 4, 641.
    Subst.: sontes condemnant reos, * Plaut. Capt. 3, 1, 16: (minores magistratus) vincla sontium servanto, Cic. Leg. 3, 3, 6: punire sontes, id. Off. 1, 24, 82: insontes, sicuti sontes, Sall. C. 16, 3: manes Virginiae nullo relicto sonte tandem quieverunt, Liv. 3, 58 fin.; Cic. Phil. 2, 8, 18; id. Fam. 4, 13, 3; Ov. M. 2, 522; 10, 697; 11, 268.
    Gen. plur.: sontum, Stat. Th. 4, 475.
  2. II. Hurtful, noxious, acc. to Fest. p. 297, 22 (but no example is preserved).
  3. III. Neutr. sing., sin, offence (eccl. Lat.), Aldh. Ep. 3.