The ability of a substance to be hammered or rolled into thin sheets is known as malleability. It is a physical property that measures the extent to which a material can be deformed under compressive stress without fracturing. Metals like gold, silver, copper, and aluminium are highly malleable and can be easily worked into different shapes through processes like forging, rolling, and hammering. Conversely, materials like glass and ceramics lack malleability and tend to break or shatter when subjected to such forces.