Shutter speed refers to the length of time the camera shutter is open, exposing light into the camera sensor, shown in seconds or fractions of a second. In laymen terms, it's how long your camera spends taking a photo.
A fast shutter speed (1/1600th second) will make it easier to photograph the subject without blur and instead freeze motion and reduce camera shakes. Using a fast shutter speed, you can eliminate motion even from fast-moving objects, like birds in flight or cars driving past.
On the other hand, with a slow shutter speed (also known as a long shutter speed) (5 seconds), you end up exposing your camera sensor for a significant period. If your shutter speed is slow, the moving subject will appear blurred along the direction of the motion.