I looked up the usage history of αἱρετικός, and it seems that our non-orthodox “heretical” meaning is used as early as Clement (Lampe). But here, in its only NT usage, it seems to be describing instead people who get partisan and argumentative about certain beliefs. The “bible code people”, referred to in a comment on the Latin board.
Ἁιρετικοί might also be a good word to describe what the internet seems to be turning us all into.
αἱρετικός, ή, όν (in Ps.-Pla., Definit. 412a; Aelian, NA 6, 59; Hierocles Stoic. [I/II A.D.] Eth. 9, 5; here 7 and Diog. L. 7, 126 also the adv.; subst. pl. οἱ αἱ. Iren. 5, 13, 2 [Harv. II 356, 8] al.) pert. to causing divisions, factious, division-making. ἄνθρωπος αἱ. division-maker Tit 3:10 (s. αἵρεσις 1b, c).—TW.
Arndt, W., Danker, F. W., & Bauer, W. (2000). A Greek-English lexicon of the New Testament and other early Christian literature (3rd ed., p. 28). Chicago: University of Chicago Press.
It is a little breathtaking to me that none of the examples cited have the meaning given in the definition, excepting the Titus passage. And in Titus (uniquely?) it seems to draw more more from αἱρετιστής than αἵρεσις, though I would strongly disagree with “division-maker” as accurately capturing the Titus sense. The Irenaeus passage cited seems to mean it as simply “heretic.”
Ah, I see, you don’t get BDAG’s organization. It normally begins an entry with earlier occurrences of the word, whether or not those earlier occurrences are used in the same sense. If the earlier usage of the word supports the NT usage, they will usually put it after the gloss.
But it never seems to be used like that again in the corpus, as the “heretical” definition takes over immediately. So this is a strangely elaborate definition for what seems to be a unique usage: