彼は頑なに自分の意見を曲げなかった。
He stubbornly refused to back down from his opinion.
何を聞かれても、彼女は頑なに口を閉ざしていた。
No matter what she was asked, she obstinately kept her mouth shut.
頑なな態度を改めない限り、話し合いは進まない。
Unless he changes his unyielding attitude, the talks won't move forward.