Jareth seems to be a blend of Jared (meaning “descent” from Hebrew) and Gareth (the name of one of the Knights of the Round Tale in Arthurian legends. The etymology behind the name is uncertain though it has been linked to Welsh gwaredd meaning “gentleness”. It could also be connected to another name, Geraint, the Welsh form of Latin Gerontius meaning “old man” from Greek geron. Other possible meanings I’ve come across is that it might be from Welsh Gweir “grass”, “hay”, “collar”, “loop” or “bend” or Gweirydd “Gweir + lord”, or that it could be from Old Welsh gwrhyt “valor”). It’s also possible that Jareth is just another spelling of Jared. The most famous (or infamous) bearer of the name is the Goblin King in the 1986 movie Labyrinth played by the iconic singer David Bowie.
Origin: Hebrew, Welsh, Ancient Greek