noun
underdevelopment; incomplete development
General term for something not having developed fully, used for physical, mental, or systemic growth.
この地域の産業は発育不全の状態にある。
Industry in this region is in an underdeveloped state.
noun
aplasia; hypoplasia; dysgenesis; infantilism
Medical term for incomplete or absent development of an organ, tissue, or body part.
先天性の発育不全により、腎臓が十分に機能しないことがある。
Due to congenital hypoplasia, the kidney may not function adequately.
未発達 also means underdevelopment but is more commonly used for skills, systems, or regions, while 発育不全 often implies a biological or medical context.
Compound of 発育 (development, growth) and 不全 (insufficiency, incomplete). The term is a straightforward Sino-Japanese medical and general expression.