A mixture of lime or gypsum, sand, and water, sometimes with fiber added, that hardens to a smooth solid and is used for coating walls and ceilings. Plaster of Paris. A pastelike mixture applied to a part of the body for healing or cosmetic purposes. Also called sticking plaster. Chiefly British An adhesive bandage. To cover, coat, or repair with plaster. To cover or hide with or as if with a coat of plaster: plastered over our differences. To apply a plaster to: plaster an aching muscle. To cover conspicuously, as with things pasted on; overspread: plaster the walls with advertising. To affix conspicuously, usually with a paste: plaster notices on all the doors. To make smooth by applying a sticky substance: plaster one's hair with pomade. To make adhere to another surface: "His hair was plastered to his forehead\u201d ( William Golding). Informal To inflict heavy damage or injury on. Informal To defeat decisively. To apply plaster.