There are two related measures of fluid viscosityĪbsolute viscosity - coefficient of absolute viscosity - is a measure of internal resistance. viscosity is the measure of a fluid's resistance to flow.The shear resistance in a fluid is caused by inter-molecular friction exerted when layers of fluid attempt to slide by one another. The viscosity of a fluid is a measure of its resistance to gradual deformation by shear stress or tensile stress. Viscosity is an important fluid property when analyzing liquid behavior and fluid motion near solid boundaries.