na-adjective
Medical/technical term referring to physical or structural changes in organs or tissues, as opposed to functional disorders. Often used in contrast with 機能的 (functional).
この症状は器質的な異常によるものだ。
This symptom is due to an organic abnormality.
器質的疾患と機能的疾患を区別する必要がある。
It is necessary to distinguish between organic and functional diseases.
Compound of 器質 (organic structure) + 的 (-like, -ic). The term is used primarily in medical contexts.