What does Sundar mean?
From Sanskrit सुन्दर (sundara) 'beautiful, handsome, lovely'. The masculine counterpart of Sundari.
What does Nagaraja mean?
From Sanskrit नागराज (nagaraja) 'king of snakes', from naga 'snake/serpent' + raja 'king' (also spelled Nagaraj in Tamil/Kannada/Telugu usage). A well-attested compound; the serpent sense is secure.