expression, godan verb (-ru)
steel oneself; brace oneself; stay on guard
Used when someone consciously tenses their mind or stays alert, often in anticipation of difficulty or pressure.
試験の前は気を張ってなかなか眠れなかった。
Before the exam, I was so on edge that I couldn't sleep.
大事なプレゼンだから、
It's an important presentation, so let's brace ourselves and go for it.