What's the difference between apostasy and heresy?

[Apostasy](https://en.m.wikipedia.org/wiki/Apostasy) >Apostasy (/əˈpɒstəsi/; Greek: ἀποστασία apostasía, 'a defection or revolt') is the formal disaffiliation from, abandonment of, or renunciation of a religion by a person. It can also be defined within the broader context of embracing an opinion that is contrary to one's previous religious beliefs. One who undertakes apostasy is known as an apostate. Undertaking apostasy is called apostatizing (or apostasizing – also spelled apostacizing). The term apostasy is used by sociologists to mean the renunciation and criticism of, or opposition to, a person's former religion, in a technical sense, with no pejorative connotation. ~ Wikipedia [Heresy](https://en.m.wikipedia.org/wiki/Heresy) >Heresy is any belief or theory that is strongly at variance with established beliefs or customs, in particular the accepted beliefs of a church or religious organization. The term is usually used in reference to violations of important religious teachings, but is also used of views strongly opposed to any generally accepted ideas. A heretic is a proponent of heresy. ~Wikipedia Is it possible to be a heretic and not an apostate and vice versa? What about in other religions like Islam?