In a solid state, the molecules is less free to move around. They are in an order, all bunched together neatly jiggling in their space. In a liquid state however, the molecules are more free to move around, they can be adjusted and moved easily.
Since the molecules can move more freely in a liquid state than a solid state, there is more disorder in the liquid state than in the solid state. This goes up the chain of states of matter by the way, from solid to liquid to gas to plasma, the disorder increases as the substance temperature increases.