member of a pre-Christian Jewish sect of uncertain origin, noted for uncompromising observance of Judaic Law. The Hasideans joined the Maccabean revolt against the Hellenistic Seleucids (2nd century BC) to fight for religious freedom and stem the tide of paganism. They had no interest in politics as such, and they later withdrew from the Maccabean cause as soon as they had regained their religious freedom. Indeed, they fell into disfavour with the Hasmonean rulers.

Tradition pictures them as so devoted to Judaic Law that martyrdom and torture were willingly preferred to the slightest violation of the Sabbath (1 Maccabees 2:42). No one can say for sure whether the Ḥasidim mentioned in the Talmud were Hasideans or not. A later sect or type, ardent in prayer and meticulous in the observance of the commandments and the Sabbath, may have been meant.

Historians tend to explain the disappearance of the Hasideans as a gradual merging with the Pharisees. The Hasideans may also have had a doctrinal influence on the Essenes, an early Jewish sect that flourished in Palestine.

Despite a similarity of names, the Hasideans played no part in the development of either the Ḥasidic mysticism of 12th-century Germany or of the more important Ḥasidic movement that arose in 18th-century Poland.