a momentary slip with serious consequences; a wrong decision made in a moment of weakness; a wrong thought on the spur of the moment
❍ 你总不能因为～，就把命都不要了？(高云览《小城春秋》171) Surely you’re not ready to die just because of your momentary slip?
一念之差yī niàn zhī chā
差：错。一个念头就错了。形容因自己一时的疏忽或考虑不周，而产生严重的后果。a momentary slip, a wrong decision made in a moment of weakness, a wrong thought on the spur of the moment