culprit

1. N-COUNT When you are talking about a crime or something wrong that has been done, you can refer to the person who did it as the culprit. 犯罪者; 犯错者

All the men were being deported even though the real culprits in the fight have not been identified. 尽管那次斗殴事件的真凶未被确认，但那些男人都在被驱逐出境。

2. N-COUNT When you are talking about a problem or bad situation, you can refer to its cause as the culprit. (造成问题或麻烦的) 原因

About 10% of Japanese teenagers are overweight. Nutritionists say the main culprit is increasing reliance on Western fast food. 约10%的日本青少年都超重。营养学家们称主要的原因是他们越来越依赖西方快餐。