The property of becoming less viscous (flow less) when it is subjected to an applied stress such as a mixing paddle. The less viscous property is only for a brief moment as it heals itself to a more viscous state with time.
Take yogurt as an example. When you first open a can of yogurt you will notice how it looks more solid because of the gel state it is in. As soon as you stick your spoon in it and stir it around a bit it immediately becomes more like a liquid.