[1] The term apostasy is derived from Ancient Greek: ἀποστάτης, meaning "rebellious"[2] (Hebrew: מורד.
"destroyed one"), and min (מין) or Epikoros (אפיקורוס), which denote heresy and the negation of God and Judaism, implying atheism.
Rabbinic categories differentiate between a mumar ledavar echad (מומר לדבר אחד) who doesn't observe a certain mitzvah, and a mumar lekhol hatorah kulah (מומר לכל התורה כולה) who doesn't observe any of the Torah.
Likewise they differentiate between a mumar l'teyavon (מומר לתיאבון) who transgresses mitzvah(s) wantonly due to craving (teyavon) or convenience, versus a mumar l'hakh`is (מומר להכעיס) meaning one who transgresses out of spite, who defies the mitzvah willfully.
[5] However today another category, tinok shenishba ("captured infant"), a Jew who sins as a result of having been raised without sufficient knowledge and understanding of Judaism, is widely applied and should be considered.
[6] In Medieval Spain, a systematic conversion of Jews to Christianity took place, largely under threats and force.