An ancient greek name (short for Themistocles). Generally Themis' are amazing party freaks, they are generally amazing in bed and can pleasure anyone for hours and hours and hours. They have black hair and green eyes. The word 'Themis' can also be used as an adjective describing a boyfriend who has all the traits described above.
Girl: Hey, whats your name
(All girls turn their heads in Themis' direction with mouths open)
Girl 1: Have you met my boyfriend?
Girl 2: No, whats he like?
Girl 1: Oh he's such a Themis!
Girl 2: Lucky girl! I wish mine was like that...