Feathering adhesive is a type of adhesive that is used to create a smooth transition between two surfaces. It is often used in construction and repair projects, such as when installing drywall or repairing a roof. The term 'feathering adhesive' comes from the fact that it is applied in a thin layer, creating a feather-like effect. The crossword solution for this term is TAR, which is a type of adhesive made from coal TAR, asphalt, or pitch.