Toughness

Name(s): 
Fragility
Hardness
Stiffness
Vulnerability
Nature

In materials science and metallurgy, toughness is the ability of a material to absorb energy and plastically deform without fracturing. Toughness is the strength with which the material opposes rupture. One definition of material toughness is the amount of energy per unit volume that a material can absorb before rupturing. This measure of toughness is different from that used for fracture toughness, which describes load bearing capabilities of materials with flaws. It is also defined as a material's resistance to fracture when stressed.

Toughness requires a balance of strength and ductility.

Source: Wikipedia

Type 
(A) Abstract fundamental problems