rabbi

Etymology

From Middle English raby, from Ecclesiastical Latin rabbi, and its source Koine Greek ῥαββί (rhabbí), from (post-Tanakh) Hebrew רַבִּי (rabbi, “my master”), from רַב (rav, “master [of]”) + ־י (-i, “me”). Compare late Old English rabbi. Doublet of rebbe.

noun

1. A Jewish scholar or teacher of halacha (Jewish law), capable of making halachic decisions.
   Next, R. Moskowitz brings us to the Slonimer Rebbe, a late 20th century Hasidic rabbi, who taught that the evil of Esav was that very sense of completion, the self-perception that he had no need for growth or further transformation. 2019, Rachel Timoner, “Book Review: Textual Activism by Rabbi Mike Moskowitz”, in Tikkun
2. A Jew who is or is qualified to be the leader of a Jewish congregation.
3. (law enforcement, slang) A senior officer who acts as a mentor.
   Hoskins? He doesn't have a better rabbi in the department than that? September 17, 2006, David Mills, “Soft Eyes”, in The Wire, season 4, episode 2, spoken by Clarence Royce (Glynn Turman)
   If I'm ever gonna make Captain, I need a good mentor. I need my rabbi. September 17, 2013, Dan Goor, Michael Schur, “Pilot”, in Brooklyn Nine-Nine, season 1, episode 1, spoken by Amy Santiago (Melissa Fumero)