A heresiarch (also hæresiarch, according to the Oxford English Dictionary) is a founder or leader of a heretical doctrine or movement, as considered by those who claim to maintain an orthodox religious tradition or doctrine. For example, according to traditional Roman Catholic doctrine, King Henry VIII of England was a heresiarch, as he influenced the Archbishop of Canterbury to break away from the Catholic Church to form the Church of England. The miller Domenicio Scandella of Carlo Ginzburg's The Cheese and the Worms was also declared a heresiarch by the inquisition judges.
Orthopraxis
is a theological term for "correct practice". Most people would probably say "lifestyle". It is rooted in the belief that Christian orthodoxy will yield, as its fruit, a Christian "orthopraxy", a way of being and living that is consistent with the social justice imperatives of the Catholic faith. The numerous contradictions between the Gospel of Jesus Christ and modern conditions suggest many areas where Christ's teachings are particularly relevant.
Turns out to be just more 'ten dollar' terms put out by the Catholic Church to mean 'it's my way (your church's way) or no way'...No biggy...
It is a biggie. Jesus established His Church (Matt 16:18,19) You reject it. And, during your Final Juddgement, you can explain to Our Lord and Saviour just why these truths are no biggies. Good luck