Viscousness is commonly used to describe the thickness or resistance to flow of a liquid. Some synonyms for viscousness include thick, dense, gooey, syrupy, glutinous, tenacious, and mucilaginous. These words can be used interchangeably to describe substances that are difficult to pour, spread, or move easily. Other related terms include stickiness, tackiness, and adhesiveness. It is important to note that different substances may have varying degrees of viscosity and the appropriate term should be used accordingly. For example, honey can be described as viscous, while molasses would be better described as syrupy.