If an activity, attempt, or plan fails, it is not successful. 失败 • We tried to develop plans for them to get along, which all failed miserably. 我们设法制定出让他们相处融洽的计划,但都惨败了。
noun [抽象名词]不及格;<非正式>过失,失败
It's the difference between a pass and a fail. 这是及格和不及格的区别。