quiver
To shake slightly with quick, small, trembling movements.
When an arrow flies through the air, it came from a quiver, the container archers wear on their back or hip to hold their arrows. Robin Hood carried a quiver full of arrows, ready to draw and shoot. Modern archers still use quivers, though today they're more likely to be competing in the Olympics.
The word also means to shake with quick, trembling movements. Your voice might quiver when you're nervous before giving a speech. A leaf quivers in a gentle breeze. A dog's ears might quiver when it hears a distant sound. This kind of quivering is different from violent shaking: it's small, rapid, and often barely noticeable.
When something quivers, there's usually a reason. Fear can make your hands quiver. Excitement might make your whole body quiver with anticipation before opening a birthday present. Even holding a difficult yoga pose can make your muscles quiver from the effort. Quivering can reveal what's happening inside, whether that's emotion, cold, exhaustion, or anticipation.