If a person is permanently outside of their physical body then they are often termed "dead", a "ghost", a "discarnate entity" or whatever. It should be remembered however that despite common belief one does not become a "spirit" when one dies. One is a spirit when one is alive. One is a spirit when one is dead. The only difference is that in the former situation one has their own physical body to return to if one is not inside it.
If one intentionally moves outside of their
body with the intention of remembering the experience then this is often
termed "astral travel". This term is used because one can not only go to
physical locations but spirit (astral) ones as well. This is a great help
if one wants to communicate with one's dead relatives and they want
to communicate with us. One can also often get help/guidance from one's
spirit guides while OOB.