Lewis & Short

† haerĕtĭcus, a, um, adj., = αἱρετικός, of or belonging to heretical religious doctrines, heretical (eccl. Lat.).

  1. I. Adj.: commissatio, Tert. adv. Haer. 41: nigredo, Arat. Act. Apost. 1, 611.
    Adv.: haerĕtĭce, heretically, Cassiod. Hist. Eccl. 5, 36.
  2. II. Subst.: haerĕtĭcus, i, m., a heretic, Tert. adv. Hermog. 27; id. de Bapt. 115; so the title of Tertullian’s work: de Praescriptione adversus haereticos.