Hyperactivity: A higher than normal level of activity. An organ can be described as hyperactive if it is more active than usual. Behavior can also be hyperactive.
People who are hyperactive always seem to be in motion. They can't sit still; they may dash around or talk incessantly. Sitting still through a lesson can be an impossible task. They may roam around the room, squirm in their seats, wiggle their feet, touch everything, or noisily tap a pencil. They may also feel intensely restless.