/'ʌndəbelɪ; `ʌndɚ,bɛlɪ/
n [sing]
1 undersurface of an animal's body, eg as a cut of meat, esp pork（动物的）下腹部（如切下的一块, 尤指猪肉）.
2 (fig 比喻) area, region, etc that is vulnerable to attack 易受攻击的部位、区域等
*The stock-market crisis struck at the soft underbelly of the US economy, eg its trade deficit. 股市危机打击了美国经济的薄弱环节（如贸易逆差）.

n [singular]literary
the unpleasant parts of a place or society that are normally hidden
underbelly of
　photographs that capture the underbelly of the United States - its poverty, its injustice, and its alienated underclass
the weakest part of an organization or a person's character, that is most easily attacked or criticized
underbelly of
　They needed to find the soft underbelly of their opponents.
the lower part of an animal's body, including the stomach