I don’t think we seriously disagree. My only insistence is that while technically true, the definition is useless in our time and place for purposes of making distinctions outside the Church, which is most of even what was Christendom. And it is difficult even within the Church. I think, for instance, those who justify divorce between two committed Orthodox Christians who both agree to continue repenting, taking up their cross and following Christ, but they just don't want to do it with their spouse, are holding to a heretical idea, for (a painful) example. But I think it merely destructive to call them heretics, so the “by definition”, though true, is more harmful than helpful. And they are in the Church, and communing, and no one says anything. (Then there are my own sins.) But the vital thing is that we admit that we are violating Church teaching and need to repent, and that refusal, that says, I don’t need to do that (whatever form the brokenness takes), and can still commune, etc, is heretical. The word winds up describing everything. So to maintain a distinction that makes the word worth anything in practical usage, it seems to me that despite the technical accuracy, it’s usage ought to be limited to those within the Church that promote or teach, by word or deed, falsehood, error, and sin.