A Rebbe or Admor is the spiritual leader in the Hasidic movement, and the personalities of its dynasties. The titles of Rebbe and Admor, which used to be a general honor title even before the beginning of the movement, became, over time, almost exclusively identified with its Tzadikim.

In Jewish law, a posek is a legal scholar who determines the application of halakha, the Jewish religious laws derived from the written and Oral Torah in cases of Jewish law where previous authorities are inconclusive, or in those situations where no clear halakhic precedent exists.