noun, noun or participle which takes 'suru', intransitive verb
Used for a gradual weakening, loss of vitality, or reduction in influence, prosperity, population, industry, culture, or physical/organizational condition. As 衰退する it is intransitive: something declines or falls into decay.
地方の商店街が衰退している。
The local shopping district is in decline.
人口の減少が産業の衰退につながった。
The population decrease led to the decline of the industry.
その帝国は長い時間をかけて衰退した。
The empire declined over a long period of time.