expression, godan verb (-ku)
exploit a gap; catch off guard
Used when someone takes advantage of a momentary lapse in attention, security, or defense. Often implies a sudden or opportunistic action.
相手の隙をついて、一気に攻めた。
I exploited an opening in my opponent's defense and attacked all at once.
彼は忙しいときの隙
He caught him off guard while he was busy and got him to sign the document.