没落

1. Origins, structure, and basic meaning

• Structure: 没落(ぼつらく) means decline through losing wealth, social standing, or influence, and forms a verb with 没落する.
• Basic usage: It is used to tell of a family's prosperity and subsequent downfall, as in the examples.

2. Common pitfalls and similar expressions

• The declining party is the subject
  • 一族が没落する means that the family loses standing or wealth. 繁栄と没落 places prosperity and downfall side by side as nouns.
• How it differs from 衰退
  • 衰退(すいたい) broadly describes weakening power or vitality. 没落 more strongly evokes a fall from previously enjoyed status or prosperity.