oily

Oily is an adjective describing substances that contain oil or are coated with oil or fat. It can refer to a physical property such as slickness or the presence of a greasy film, and it can also describe something that resembles oil in texture or appearance. In figurative usage, oily can describe a person or manner perceived as slick, smooth-talking, or untrustworthy.

In everyday language, oily is often used to classify foods rich in fats or cooking oils. Oily foods include fried dishes and certain sauces or dressings. In personal care and health contexts, the term commonly describes the skin or hair when sebaceous glands produce excess sebum, resulting in a shiny complexion or oily, heavy hair. Treatments emphasize regular cleansing with non-comedogenic products to manage shine and prevent clogged pores.

In science and industry, oily can describe materials that are lubricated with oil, or surfaces carrying an oil film. Oil films can reduce friction but may attract dust or contaminants and pose challenges for cleaning and environmental control. In environmental contexts, an oil spill creates an oily sheen on water that harms ecosystems and requires specialized containment, cleanup, and remediation efforts.

Etymologically, oily derives from oil plus the suffix -y, indicating a resemblance or association with oil. The term is widely used across disciplines, with meanings converging on the presence, appearance, or perception of oil or grease.