A Zeem is a type of person who is usually between the ages of early teens to late twentys. This type of person is usually one who is more likely to stay inside of his room and be less social with the peers of his own age, and instead will feel more comfortable playing video games (like World of Warcraft and Burnout Revenge) and watching Japanese Animation (Like Pokemon and Yu-Gi-Oh!). Because of the fact that the stay indoors they will most likely be more self-concious of their physical appearance (e.g. poor dental quality, poor complexion) and so they will find it deifficult to mix with peers. And because of this, they will find a person/people of a younger age to make friends with.
Guy 1: What happened to Martin?
Guy 2: Oh he became a Zeem!
Guy 1: A what?
Guy 2: Basically he stays inside playing games and worrying about his appearance and breath.