Heresy is not a property a belief can have on its own. It is a relation between a belief and an authority that has rejected it, and any sentence using the word is incomplete until the authority is named.
Consider what is actually being said. To call a doctrine heretical is to report that some body has condemned it. The same doctrine is orthodox somewhere else, held in good conscience by people whose own authorities have examined it and approved it. Miaphysite christology is heresy by the standard of Chalcedon and is the faith of the Coptic and Armenian churches. Arminianism is error by the Canons of Dort and is the ordinary teaching of world Methodism.
There is no view from nowhere available here, and writing as though there were is a way of adopting one party's judgement while appearing to state a fact.
The word did not start out hostile
The Greek meant a choice, then a school or faction, with no pejorative force, it is used neutrally of the Pharisees and Sadducees. It acquires its later sense only as Christianity develops the idea of a single deposit of faith from which one can deviate.
That structure is not universal. It requires a body competent to define the deposit and a boundary that can be crossed, and a great many religious traditions have neither.
The technical distinctions do real work
Catholic canon law defines heresy narrowly: the obstinate denial or doubt, after baptism, of a truth to be held with divine and catholic faith. Obstinacy is required. This separates formal heresy, which is culpable, from material heresy, which is error held in good faith, and it is what allows the tradition to call a proposition heretical without condemning everyone who holds it.
Heresy is further distinguished from apostasy, the total repudiation of the faith, and from schism, the refusal of communion. The three are regularly confused in ordinary usage.
Traditions that do not have it
Judaism has terms of censure but has policed practice far more than assent, and holds that a Jew who has sinned, or converted out, remains a Jew. Hinduism has no body competent to define orthodoxy across the tradition; schools that flatly contradict each other on the nature of the self coexist as schools. Jainism's doctrine of many-sidedness treats a one-sided assertion as a partial view rather than an offence.
These absences are not gaps waiting to be filled. They are structural facts about how those traditions are organised, and they are a reason to be careful with a word that assumes the opposite.