underbelly

1. N-COUNT The underbelly of something is the part of it that can be most easily attacked or criticized. 弱点

I know where his soft underbelly is, and that's his material possessions. 我知道他的弱点是什么，是他的财产。

2. N-COUNT The underbelly of an animal or a vehicle is the underneath part of it. 腹部

The missiles emerge from the underbelly of the transport plane. 导弹从运输机的腹部发出。