There are dozens of rabbis named Yehuda in the Talmud, and none is more prominent than Rav Yehuda bar Yehezkel. He is referred to solely by title and first name, Rav Yehuda, not needing a patriarchal identifier to separate him from all the others.
We encounter Rav Yehuda on today’s daf following a suggestion by the Gemara that the two clauses of the mishnah under discussion represent two different positions. To support the claim that this is possible, the Gemara cites Shmuel who is discussing a different mishnah:
Shmuel said to Rav Yehuda, “Shinnana, leave the mishnah and follow after me that the first clause is the opinion of Rabbi Tarfon and the last clause is the opinion of the rabbis.”
A number of medieval talmudic commentators suggest that the nickname Shmuel uses for Rav Yehuda, Shinnana, is derived from the word shinun, which means sharp, as in sharp-minded. That his teacher praised him this way suggests that Rav Yehuda had begun to separate himself from the rabbinic pack early in his career. But as some earlier commentators suggest, Rav Yehuda might have acquired his nickname for completely different reasons. Shinnana, they suggest, comes from the word shen, meaning tooth:
Rav Yehuda was known for having the biggest of teeth … While some say that Shinnana means “teacher of law” [shoneh halachot] … such an interpretation is just talk. This is evident in the current usage of the word — anyone with big teeth, we call Shinnana.
So Shinnana may mean “big tooth.” Instead of praising Rav Yehuda for his sharp intellect or his accomplishments as a teacher and legal scholar, Shmuel is actually calling out a unique physical feature.
It makes sense that many commentators would lean toward the first interpretation. Both Shmuel and Rav Yehuda come out looking better if the comment is about rabbinic acumen. But if we are looking to understand what Rav Yehuda’s nickname really means, it’s the earlier interpretations that are probably most accurate. Why? Because they come from the academies of the Geonim, the rabbinic leaders of the Babylonian Jewish community during the post-talmudic period. And given their proximity to the Babylonian Talmud in terms of time and space, they had a more intimate connection to the language of the Talmud (especially colloquialisms like nicknames) than their colleagues who lived a few centuries later in central Europe and North Africa and did not speak Aramaic as their vernacular.
It may be that Rav Yehuda embraced his largeness of tooth and took pride in being known for his unique canines. Teeth, of course, have their sharpness, which may be why shen and shinun are connected linguistically. So perhaps, an appellation that began as praise from his teacher was transformed into ridicule by his peers.
Rav Yehuda is quoted often in the Talmud and his legacy outshines a large majority of his peers. So too, it appears, did the glimmer of his smile, given the ample surface area of his pearly whites.
Read all of Bava Kamma 14 on Sefaria.