The personal name Rubish likely originated as an analogy to the Slavic formation Grubish, which means 'fat one'. This name probably lost its initial palatalized /Ь/ under the influence of Hungarian or Polish languages. The earliest mention of the name Rubish comes from the northern Hungarian counties of Bihar and Szabolcs. For example, in 1219, there is a record of Rubizo ioubagio (Reg Var 220). In 1308, the name Rubisz is also mentioned in Poland (SSNO IV 509). Interestingly, in written records of the Polish language, the variants of the surname Rubieszewski and Hrubieszewski were used simultaneously (see SSNO VII 213). In 1649, a Cossack named Rubysh Kyslenko is mentioned in the city of Cherkasy (RVZ 77). From the 18th century, the anthroponym Rubish has been recorded in Transcarpathia and the Podhorye region, and in Serbia, names such as Grubash, Grubesha, and Grubish are still in use, originating from the adjectival root 'gruby', meaning 'fat'.
