Malleability refers to the ability of a material to undergo plastic deformation when subjected to compressive force. It is the property that allows a material to be hammered or rolled into thin sheets without breaking or cracking. Malleability is a desirable characteristic in many materials, as it enables them to be shaped and formed into various objects and structures.

Plastic Deformation
Plastic deformation is a permanent change in the shape or size of a material under the action of an applied force. When a compressive force is applied to a material, the atoms or molecules within the material are displaced from their original positions. In an elastic material, this deformation is temporary and the material returns to its original shape once the force is removed. However, in a malleable material, the deformation remains even after the force is removed.

Explanation of other options:
- Ductile material: Ductility is the ability of a material to undergo plastic deformation without breaking or cracking. While ductility is related to malleability, it specifically refers to the ability to deform under tensile forces (stretching) rather than compressive forces (squeezing). Therefore, option B is not the correct answer.
- Plastic material: The term "plastic" is often used to refer to materials that can be molded or shaped under heat and pressure. While plastic materials can undergo plastic deformation, the term itself does not specifically refer to the response of a material to compressive force. Therefore, option C is not the correct answer.
- Elastic material: Elasticity is the ability of a material to deform under stress and return to its original shape when the stress is removed. Elastic materials do not undergo permanent deformation and do not exhibit malleability. Therefore, option D is not the correct answer.

Conclusion
In summary, the correct answer is option A - malleability. Malleability is the property that allows a material to undergo plastic deformation when subjected to compressive force. It is a desirable characteristic in materials that need to be shaped or formed without breaking or cracking.

Malleability is a material's ability to undergo deformation under compressive force without breaking or cracking, typically referring to the ability to be hammered or rolled into thin sheets. When a malleable material experiences a force, it responds by deforming instead of shattering. This quality is especially important in metalworking where metals are often subjected to high levels of compressive stress.