What does Nagendra mean?
Sanskrit compound of naga 'serpent' + Indra (as the suffix -endra 'lord, chief'), read as 'lord/king of serpents'. Hedge: the naga element is secure, and this split is the standard reading, but I could not confirm the full compound against a Sanskrit lexicon rather than name-reference sites, so treat the exact gloss as the common interpretation.
What does Varuna mean?
In Vedic Hinduism Varuna is the deity of the waters, oceans, rivers and the celestial waters. The name is Sanskrit; later tradition firmly associates him with the sea and all water.