/ˈʌndəbeli ||; ˈʌndɚˌbɛlɪ/noun[sing] 1 the weakest part of sth that is most easily attacked 脆弱点；薄弱环节: The trade deficit remains the soft underbelly of the US economy. 贸易赤字仍是美国经济的软肋。
2 the underneath part of an animal ﹙动物的﹚下腹部，腩: (figurative 比喻) He became familiar with the dark underbelly of life in the city(= the parts that are usually hidden). 他逐渐熟悉都市生活的阴暗面。