澄み切る

1. Origins, structure, and basic meaning

• Structure: 澄み切る, read すみきる, combines 澄む, to become clear, with 切る, which here marks completeness.
• Basic usage: It is an intransitive verb for the sky or water reaching a completely clear state.

2. Common pitfalls and similar expressions

• Completeness from 切る
  • Here 切る does not mean physically cutting; it emphasizes that the clearing is complete.
• Observed state and nonpast
  • 澄み切っていた describes a clear state observed in the past, while 澄み切る describes a general change on winter mornings.