Viscosity is a measure of a fluid's resistance to flow. It's a physical property of fluids. In simple words, viscosity shows resistance to flow. Some liquids with low viscosity are- Water, Ether, Chloroform, Acetone etc. Most of the low viscous fluids are non polar with mow intermolecular forces. High viscosity means that the friction between two layer is high. So the liquid will flow slowly. For example, Vegetable oil, mercury, glycerin and many more.