Since there is no apparent Hebrew, Germanic, or Slavic source for it, scholars have looked for a Romance provenance and come up with two possibilities: one is Ancient Greek Φοῖβος (Phoîbos), a word meaning “bright” or “shining,” used by the ancient Greeks as an epithet for the god Apollo, perhaps through Latin Phoebus. Although nothing like it can be found in ancient Jewry, we come across it in the 17th century, when well-known Polish rabbi Shmuel ben Uri Shraga Faybish (or Fayvush) spelled his name “Phoebus” in Latin characters, as did his descendants. Further strengthening the case for it is the frequent Eastern European combination Shraga-Fayvush (or Fayvl), since "shraga" means “light” in the Aramaic of the Talmud. See שְׁרָגָא (shraga), a cognate of Arabic سِرَاج (sirāj) and Classical Syriac ܫܪܓܐ (shraga). Jews often gave children double names, joining Hebrew-Aramaic ones to parallel ones in the local language, and Shraga-Fayvush might be the Yiddish form of an earlier Mediterranean Jewish doublet that has been lost. The Hebrew name אורי ("Uri"), it should be pointed out, comes from אור ("or"), which means “light,” too.
Yet an alternate theory holds that Fayvush-Fayvl descends from Latin vivus (“living”), which we also find translated into Hebrew as חיים (hayyim), and that the spelling of “Phoebus” is a 17th-century affectation. A Jewish family called Vives can be found in 12th-century Barcelona, and the name existed among other Spanish Jews. And for that matter, consider also the possibility that Fayvush/Fayvl comes from the Roman name Fabius, from Latin Fabius, or its Italian form, from Old Italian Fabio.
פֿײַוול • (fayvl) m