What does Dev mean?
From Sanskrit deva (देव), 'god, deity, divine one', from a root meaning 'to shine'. A simple, ancient word meaning 'divine'.
What does Neel mean?
From the Sanskrit नील (nīla), 'dark blue, indigo, sapphire'. A genuine classical colour word, also the root of 'neelam' (sapphire). Note: the similar-looking English/Irish name Neil (from Gaelic Niall) is a separate, unrelated name.