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 Yuvan mean?
From Sanskrit yuvan (युवन्), 'young, youthful', and as a noun 'a youth, young man'; the dictionary sense also extends to 'strong, healthy'. A well-attested classical word.