Of unclear and disputed origin, it is likely that it was derived from an exonym from neighboring groups to the north, such as Hausa, Fulani, or Bariba. Various implausible etymologies have been proposed, often used to insult the Yoruba people or support supposed Middle Eastern or Jewish origins of the Yoruba people. What is certain is that the term was used originally in reference to only the Ọ̀yọ́ people (a subgroup of the Yoruba ethnic group) and the Oyo empire, and did not become used to refer to all Yoruba peoples until the late 19th century during attempts to foster a common ethnic identity. Etymological theories include: * Several folk etymologies associate the term from coming from Hausa or Fula slurs of Yoruba people, such as Hausa ya rība meaning "One who cheats," referring to the supposed deceitful tactics Yoruba traders used, or Hausa ya ruba meaning "Bad or rotten person." These have been dismissed and proscribed by most Yoruba scholars, however, the Yoruba term yóóbá is derived from the first etymology, but is not to be mistaken with "Yoruba." *According to linguist Kọlá Túbọ̀sún, it ultimately derives from a contraction of yārṑ + ọba "Children of the Ọba", (referring to the Alaafin of Oyo). * A newly proposed theory suggests it is a reborrowing from the word Yàgbà, a Yoruba subethnic group, borrowed into the Nupe and Hausa languages, where it became Yarba, and then reborrowed from Hausa Yarbanci