Can anyone illuminate the etymology of בָּהִיר (bahir)?

ANSWER: The etymology of בָּהִיר is clear. According to Cheshek Shlomo, the underlying biliteral root is בר (“outside”) which, in turn, is the the root of ברור, clarity. Among the other derivatives of this root are: בורית (soap), בירה (capital, the city or building that stands out prominently and clearly from the others), בר (cleansed), באר / ביאור (clarifications, explanations), בהרת (a bright clear spot), ברותים (a species of especially prominent tree which stands out from the others).

Rabbi Yehoshua (Jeremy) Steinberg