Explanation

Toughness: When a huge external force is applied on a metal, the metal will experience fracture. Toughness is the ability of a metal to resist fracture. The ability of a material to resist fracture due to high impact loads, is called toughness.

Malleability: It is the property by which a metal can be rolled into thin sheets. Highly malleable metals (like Mild Steel) are extensively used in making sheet metals.

Brittleness
Brittleness is a property of material which breaks with little or no deformation.

Hardness: Hardness is the ability of a metal to resist permanent change of shape caused by an external force.