腕組み

1. Origins, structure, and basic meaning

• Structure: 腕組み(うでぐみ) combines 腕, arms, and 組み, arranging them together. In these examples it means folding one's own arms.
• Basic usage: It describes an arms-crossed posture while looking at a model or thinking about an answer.

2. Common pitfalls and similar expressions

• Maintaining the posture with まま
  • 腕組みしたまま means keeping the arms folded while doing something else. In the example, the person remains in that posture while thinking.
• Noun and verb expressions
  • 腕組みをする and 腕を組む can describe the same posture here. The former adds する to a noun; the latter makes the arms the verb's object.