also: ふちのやまい
noun
incurable illness; incurable disease
Refers to a disease that cannot be cured. Often used in serious or literary contexts.
彼は不治の病にかかっていると診断された。
He was diagnosed with an incurable illness.
不治の病と闘う患者を支援する団体がある。
There are organizations that support patients fighting incurable diseases.
難病 refers to a disease that is difficult to cure or treat, often used in medical and legal contexts (e.g., intractable diseases). 不治の病 emphasizes the incurability and has a more literary or dramatic tone.
不治 is a noun meaning 'incurability' and is often used in compounds like 不治の病. It is less common as a standalone word.
Compound of 不治 (fuji, 'incurable') + の (possessive particle) + 病 (yamai, 'illness'). 不治 is a Sino-Japanese word (kango) from 不 (fu, 'not') and 治 (ji, 'cure').