凝る

1. Origins, structure, and basic meaning

• Structure: 凝る is read as こる and is an intransitive verb meaning for muscles to become stiff or for someone to become deeply absorbed and elaborate in a hobby or activity.
• Basic usage: Shoulder stiffness after sitting for a long time appears in 肩が凝る, while becoming absorbed in model making appears in 模型作りに凝る.

2. Common pitfalls and similar expressions

• Bodily stiffness and deep absorption
  • Particles and context distinguish a body part becoming tight from pursuing an interest down to detailed tools and methods.
• Difference from 夢中になる
  • Unlike the broad expression for becoming completely absorbed in something, this verb also describes bodily stiffness and can suggest taking elaborate care over a hobby.