: "Un" is an English prefix meaning
: "reversal," as to undo a mistake or look
: at an unmade bed.
: "Undeath" means reversal of death . The
: reversal of death is to animate a thing that died,
: however long its period of death was (which can even
: be considered to coinside with undeath).
: "Unlife" means "reversal of life."
: The reversal of life is death, non-existance. Shades
: surely exist, however, and are clearly more than dead.
: This is why your term is faulty.
Actually, "unlife" wouldn't be simple death, otherwise undeath would be simply life. But undeath, as you say, is the reversal of the dying process, to make a dead thing as though it hadn't died, returning it to its previous state of life.
But a living thing having it's state reversed isn't killing it; it's unbirthing it. So if something was made "unalive", by these strictly literal terms, then it would be unmade entirely, as though it had never been born. Or rather, some sort of perverse facsimily of having not been born, though I can't think of any way that that would work, besides maybe just stripping the soul from a body, leaving it an empty, inanimate, living shell, the same way, undead are empty, reanimated, dead shells.