Names that don't have meanings like that are normally made up. A few names are so old that their roots are untracable. Names are made up of different roots, which cause them to have meanings.
Elizabeth is a Greek from of
Elisheba.
Elisheba has the roots El - which is God. The rest I can't explain.
Melanie is another example. It means black, dark, and is dervived from the word melaina.
Liza