A viscous substance is a thick, sticky liquid that has a high viscosity. Common examples of viscous substances include GLUE, OIL, SLIME, GOO, TAR, and GOOP. GLUE is a type of adhesive that is used to stick two objects together. OIL is a type of liquid hydrocarbon that is used in lubricants and fuels. SLIME is a type of viscous material that is often made from a combination of borax and GLUE. GOO is a type of sticky, slimy substance that is often used as a children's toy. TAR is a type of dark, viscous material that is derived from the distillation of coal or wood. GOOP is a type of viscous material that is often used as a sealant or adhesive.