開襟

1. Origins, structure, and basic meaning

• Structure: 開襟 is read かいきん and means opening a collar or the form of an open collar.
• Basic usage: It is used for opening a shirt collar in the heat or describing an open-collar shirt worn in summer.

2. Common pitfalls and similar expressions

• Action and garment type
  • 開襟して describes the action of opening the collar. 開襟シャツ names a shirt with a collar designed to lie open.