Hunting oscillation is when something keeps moving back and forth, like a swing or a pendulum. Imagine you're on a swing and you kick your legs out to go higher. When you get to the highest point, you start to slow down and eventually you start to swing back down. But as you swing down, you start to speed up because of gravity. You eventually swing through the lowest point and start to go higher again, but now you have too much momentum and you start to slow down again, which brings you back to the middle, and the cycle repeats itself. That's basically what hunting oscillation is. It happens when there is some kind of force that is causing something to move, but that force is unstable, so the thing keeps moving back and forth instead of staying in one place.