Do the theologians actually discuss the term "formal heretic"?
I've seen "manifest heretic", "notorious heretic", and "public heretic" (and, of course, the heresy has to be pertinacious), but I've not seen "formal heretic" except in recent years.
Of course, there is "formal heresy" as opposed to "material heresy", but I've not seen the adjective, formal, applied to the person before.
Can you point me to the appropriate theologians? I'd like to see how the term is explained.