[Facts] Re: Nikodemos vs Demonikos
In principle, the first part determines the second one, so Nikodemos would come out as "victorious people" and Demonikos as "popular victory". However, for given names this kind of reasoning is moot because the name elements have taken their own life independent of the nouns of the common language. In the end, both names are just composed of the elements "demos" and "nike" with an already bleached out meaning.