崩れる

1. Origins, structure, and basic meaning

• Structure: 崩れる, read くずれる, means losing one's shape or structure and collapsing or falling apart.
• Basic usage: In 大雨で石垣の一部が崩れた。, part of the stone wall collapsed in heavy rain.

2. Common pitfalls and similar expressions

• Objects and plans
  • 石垣の一部が崩れた describes a physical collapse; 予定が崩れて describes a disrupted plan. As the verb is intransitive, が marks what falls apart.