(~s)
1.
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 ~.
All the men were being deported even though the real ~s in the fight have not been identified.
= offender
N-COUNT: usu the N
2.
When you are talking about a problem or bad situation, you can refer to its cause as the ~.
About 10% of Japanese teenagers are overweight. Nutritionists say the main ~ is increasing reliance on Western fast food.
N-COUNT