It is the hypothetical source of/evidence for its existence is provided by: Greek pharao "I plow;" Latin ferire "to knock, strike," forare "to bore, pierce;" Lithuanian barti "to scold, accuse, forbid;" Old Church Slavonic barjo "to strike, fight," brati "to fight," Russian borot "to overpower;" Albanian brime "hole;" Old English borian "to bore through, perforate," Old Norse berja "to beat, hit," Old High German berjan "to hit, pound, knead."
<a href="https://www.etymonline.com/word/Boris">Etymology of Boris by etymonline</a>
Harper, D. (n.d.). Etymology of Boris. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/Boris