This is one of the most popular of the Weapons of Oppression. It is also one of the most subtle and insidious. Exhaustion is all about taking away resources, options, possibilities, and opportunities.
One easily-recognized form of exhaustion is being literally tired - mentally, physically, emotionally. Capitalism in particular loves to work us into this state. If we are exhausted from just trying to stay alive, we have nothing left with which to build better options for how to live.
But exhaustion also shows up in other ways, like denying people choices, or preventing access to things that everyone should have a basic right to, such as shelter, food, medical care, community, self-expression, and so on.
Exhaustion is very often combined with the other weapons of oppression. Division is frequently used as an excuse to take resources away from one set of people (thereby exhausting them) and giving those things to other people. Idea control is often used to keep us from learning ways to defend against our exhaustion, or to think up ways to redistribute resources to help mitigate exhaustion.