well weariness is also a vague concept as well… you could say that reading a book could or could not cause you weariness, depending on if you’re enjoying reading the book or if its a particularly thick and boring concept, but we already have the joy meter for that… your character enjoys reading a book they enjoy and dont enjoy reading what they dont.
prolonged activity of doing something over and over and over again will cause weariness… theres two definitions though, and so actions that take a lot of physical strength (like chopping down a tree) cause fatigue (in the form of weariness)
regardless, sitting around not doing anything for several minutes in game, or making your character take a couple hour nap, will remove most if not all of your weariness.