Characters in Game of Thrones whose status is uncertain at this stage of the tale, as revealed in the TV series. They are missing, or their whereabouts are unknown. They might be dead, they might be alive - we simply do not know.
Characters who play a part in the books but of whom it is not certain whether they'll appear in the TV series, are labeled as Status: Alive. Unless, of course, the books proclaim them to be dead at the current stage of the TV series.