underbelly

noun

1. The underside of an animal.

   “We identified the species of the snake by its blue-grey underbelly.”

   “The soft underbelly of the dragon. In the legend, the dragon's armor doesn't cover its stomach.”

   “The biologist and his team were greeted by a nonstop squid review, with Humboldt squid darting in toward the boat and flashing their underbellies in attempts to lure small schooling fish near the surface.”

2. The underside of any thing.

   “A jolt told me that the Nautilus had bumped the underbelly of the Ice Bank, still quite thick to judge from the hollowness of the accompanying noise.”

3. (figuratively)The side which is not normally seen, normally a dark, immoral place.

   “The area by the canal is the underbelly of town – not something you’d see in the guidebooks.”

   “In order to take the initiative, military leaders from Great Britain and the United States decided to attack in Africa, cross the Mediterranean, and move up against the "soft underbelly" of German-dominated Europe.”

   “The documents in this report reveal how such doctrinal disagreements have historically driven wedges within the upper echelons of al-Qa'ida. It is this intra-movement contention that comprises the soft underbelly of violent jihad, which can be exploited to great ends.”

   “Twenty-one years after the movie "Trainspotting" gave the world a glimpse into Edinburgh's seedy, heroin-filled underbelly, the franchise is back on the map with “T2 Trainspotting.””

   “The book arrives at a moment of reckoning for the running world, as more female runners have come forward to share their stories of the sport’s dark underbelly, one that can be rife with manipulation, eating disorders and physical and emotional abuse.”