An oily substance is a type of organic compound that is composed of carbon, hydrogen, and oxygen atoms. The most common examples of oily substances are GREASE, lipids, and fats. GREASE is a thick, oily liquid made from animal or vegetable fats and is used as a lubricant or sealant. Lipids are a group of organic compounds that are insoluble in water but soluble in organic solvents. Fats are a type of LIPID that are solid at room temperature and are used for energy storage in the body.