Meaning

noun spiritual leader of a Jewish congregation; qualified to expound and apply Jewish law

noun a Hebrew title of respect for a Jewish scholar or teacher

originFrom 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”) + ־ִי (-í, “my”). Compare late Old English rabbi. Doublet of rebbe and related to rav.

Etymology from Wiktionary, CC BY-SA 3.0