Radagast

In Unfinished Tales of Númenor and Middle-earth, Christopher Tolkien indicates that his father intended to change this derivation and bring Radagast in line with the other wizard-names Gandalf and Saruman, by associating it with the old language of the Men of the Vales of Anduin. No alternative meaning is provided (indeed, Tolkien stated that the name was 'not now clearly interpretable'). One possible source (a somewhat unfounded conjecture) would be Old English rudugást, 'brown spirit' (rudu strictly means 'red' or 'red-brown' - it is the source of the modern word 'ruddy').