Apparently Google has just indexed Orr's article (although they date it to 1993): . He writes that "...Radagast and Variag, which were obviously taken from Slavic originals, and are recognised as such by all the critics." The latter statement seems a bit vague to say the least. And then there's a treatise by Clive Tolley in "Old English influence on The Lord of the Rings" where he writes that Radagast "is derived from Slavonic" (aka Slavic) . Anyhow, the etymology of Tolkien's characters should either be treated in a relevant stand-alone article or in J. R. R. Tolkien's influences, but not in this article about The Hobbit.