noun
gird oneself up; brace oneself; prepare for a challenge
A yojijukugo meaning to tighten one's loincloth and give one's all, used for mentally preparing for a decisive effort or confrontation.
試験の前日、彼は緊褌一番の覚悟で最後の追い込みをかけた。
The day before the exam, he girded himself up and made a final push.
社長は緊褌一番、新プロジェクトの成功を誓った。
The president braced himself and vowed to make the new project a success.