Ῥαββεί (with ι or ει ) occurs frequently in the NT; ῥαββουνεί (with single or double β , and ι or ει ) appears at Mark 10:51 and John 20:16 (web addresses 1 & 2).
The Hebrew רבי rabbi means "my master"; it was a term of address and an honorific for scholars and teachers in the Hebrew of the first century CE and thereafter.
The present entry ignores (e.g.) the NT Catenae, where these terms are glossed with the Greek word didaskalos, teacher; but Adler reports similar glosses in the Ambrosian Lexicon.