Slicker material is a term used to describe OILSKIN, a type of fabric that is made from cotton or linen and treated with linseed oil. OILSKIN is waterproof and windproof, making it an ideal material for outdoor clothing and accessories such as raincoats, hats, and boots. It is also commonly used in the construction of sails and tents. OILSKIN is a durable material that can withstand harsh weather conditions and is often used by sailors and fishermen.