脆化 (cuì huà) is a technical noun meaning 'embrittlement' — the loss of ductility and toughness in a material, making it more prone to sudden fracture under stress. The character 脆 (cuì) means 'brittle' or 'crisp', conveying fragility and lack of flexibility; 化 (huà) means 'to change' or 'transformation', indicating a process or state shift. Together, they denote the progressive degradation of mechanical properties, especially in metals, polymers, or biological tissues.

This term appears frequently in materials science, engineering, and medical contexts — for instance, when describing age-related stiffening of arteries or collagen breakdown in aging skin. It is formal and specialized; rarely used in casual speech. While originally from metallurgy, its usage has expanded into biomedical literature to describe pathological tissue hardening or functional decline due to structural changes.