Viscous means sticky, gluey and syrupy. So if something is viscous, you usually don't want to stick your fingers in it — that goes for boogers and maple syrup alike. A viscous fluid is any liquid or gas that resists flowing freely, caused by internal friction between its molecules as they move past each other. The higher the viscosity, the slower and thicker the fluid behaves. Honey is a classic example: pour it from a spoon and it moves sluggishly compared to water, which splashes and spreads almost instantly. That resistance you can see and feel is. VISCOUS definition: of a glutinous nature or consistency; sticky; thick; adhesive. See examples of viscous used in a sentence. Viscosity is the material property which relates the viscous stresses in a material to the rate of change of a deformation (the strain rate). Although it applies to general flows, it is easy to visualize and define in a simple shearing flow, such as a planar Couette flow. Dynamic viscosity is a material property which describes the resistance of a fluid to shearing flows. It corresponds roughly to the intuitive notion of a fluid's 'thickness'. For instance, honey has a much higher viscosity than water. Viscosity is measured using a viscometer. Measured values span several orders of magnitude. Of all fluids, gases have the lowest viscosities, and thick liquids. The meaning of VISCOUS is having a thick or sticky consistency : viscid. How to use viscous in a sentence. Define viscous. viscous synonyms, viscous pronunciation, viscous translation, English dictionary definition of viscous. adj. 1. Having relatively high resistance to flow. 2. Viscid; sticky. vis′cous·ly adv. vis′cous·ness n. American Heritage® Dictionary of the English. Mastering words like viscous elevates your language, making descriptions more precise and engaging. Whether in professional writing, casual conversation, or storytelling, knowing when and how to use such words adds depth and clarity. VISCOUS definition: 1. A viscous liquid is thick and sticky and does not flow easily. 2. A viscous liquid is thick and…. Learn more. viscous (comparative more viscous, superlative most viscous) Having a thick, sticky consistency between solid and liquid (that is, a high viscosity).