Vlach (n.)

Old English Wielisc, Wylisc (West Saxon), Welisc, Wælisc (Anglian and Kentish) "foreign; British (not Anglo-Saxon), Welsh; not free, servile," from Wealh, Walh "Celt, Briton, Welshman, non-Germanic foreigner;" in Tolkien's definition, "common Gmc. name for a man of what we should call Celtic speech," but also applied in Germanic languages to speakers of Latin, hence Old High German Walh, Walah "Celt, Roman, Gaulish," and Old Norse Val-land "France," Valir "Gauls, non-Germanic inhabitants of France" (Danish vælsk "Italian, French, southern"); from Proto-Germanic *Walkhiskaz, from a Celtic tribal name represented by Latin Volcæ (Caesar) "ancient Celtic tribe in southern Gaul."

As a noun, "the Britons," also "the Welsh language," both from Old English. The word survives in Wales, Cornwall, Walloon, walnut, and in surnames Walsh and Wallace. Borrowed in Old Church Slavonic as vlachu, and applied to the Rumanians, hence Wallachia. Among the English, Welsh was used disparagingly of inferior or substitute things (such as Welsh cricket "louse" (1590s); Welsh comb "thumb and four fingers" (1796), and compare welch (v.)). Welsh rabbit is from 1725, also perverted by folk-etymology as Welsh rarebit (1785).

also Walach, one of a Rumanian people, 1786, from German Wallache, from Old Church Slavonic Vlachu, from Old High German wahl "foreigner, one speaking a foreign language" (see Vlach). Related: Wallachia; Wallachian.

1520s, of a people of what is now souther and southeastern Belgium, also of their language, from French Wallon, literally "foreigner," of Germanic origin (compare Old High German walh "foreigner"). The people are of Gaulish origin and speak a French dialect. The name is a form of the common appellation of Germanic peoples to Romanic-speaking neighbors. See Vlach, also Welsh. As a noun from 1560s; as a language name from 1640s.