system
Given the following post, respond as if you're commenting on Reddit:
human
[Discworld] Do Werewolves die of old age?

I know they're kind of undead, but they're not like ... *proper* undead, right?
gpt
In Discworld, "undead" is more realistically defined as "damn near unkillable by normal means".  A troll may be hard to kill, but will still go down with enough smacks from a sword, as opposed to a vampire, which only goes down with holy water or sunlight and will come back eventually.

Werewolves are only really harmed by silver - they heal quickly from other wounds.  Since this is not a common choice of weapon (because that's just expensive), people treat this as a big enough a challenge to move werewolves into the "undead" category.

Compare this with Elves, who are more deadly and technically harder to kill than werewolves, but are not treated as undead.  This is partially because other than (most) witches and blacksmiths, most people forget that elves are a real threat, but is also because their main weakness is iron.  Since most simple weapons (and impromtu weapons, like a fry-pan) are made from iron, the ones that fight back are too caught up in the moment to analyze exactly which weapons work and which don't (other than maybe "a sword hurts more than a stick", which isn't much of an observation) and those that try to fight back with anything other than iron either end up charmed or dead.

Anyway, Werewovles might die from old age (though there's no evidence for or against this in the books).  But that's a property exclusive to being labeled "undead".