頑固

1. Origins, structure, and basic meaning

• Structure: 頑固 is read as がんこ and describes something stubborn or persistent that does not readily change.
• Basic usage: It can characterize a person who will not change an opinion or a stain that is difficult to remove.

2. Common pitfalls and similar expressions

• A person's attitude
  • 頑固な人 is someone who does not readily change an opinion once a decision has been made. Example: 父は一度決めると意見を変えない頑固な人です。
• A persistent condition
  • 頑固な汚れ means a stubborn stain that is hard to remove. Example: 頑固な汚れを落とすため、布を水に浸しました。