mole1

noun

• 1a small burrowing mammal with dark velvety fur, a long muzzle, and very small eyes, feeding mainly on worms, grubs, and other invertebrates.

  • Family Talpidae: several genera and species, including the European mole (Talpa europaea)

• 2a spy who gradually achieves an important position within the security defences of a country: a well-placed mole was feeding them the names of operatives
• someone within an organization who anonymously betrays confidential information: the company is hunting for the mole who revealed details of planned job cuts