underbelly /ˈʌndəˌbɛlɪ/

• 1. 

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

  例：

  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

  例：

  The missiles emerge from the underbelly of the transport plane.

  导弹从运输机的腹部发出。