The term THICK FATTY OIL can be summarized as GREASE, a 6-letter word. GREASE is a lubricant composed of a thick, oily, and viscous liquid or semi-solid that is used to reduce friction between two surfaces. It is typically made from petroleum-based products, such as mineral oil, or from animal fats. GREASE is often used in automotive applications, such as on car engines, and in industrial settings, such as on machinery.