expression, godan verb (-ru)
suffer an embarrassing defeat; make a blunder
Used when someone makes a careless mistake or suffers a humiliating loss, often in competition or personal conduct. The phrase implies a loss of face or a failure one should have avoided.
油断して不覚を取った。
I let my guard down and suffered an embarrassing defeat.
彼は簡単なミスで不覚を取り、
He made a simple mistake and lost face.