Related Clues:

• Shadow, maybe
• Bond, for one
• Spy on the inside
• Northern ___ (apple)
• Smart or Bond, e.g.
• Burrowing rodent
• Breakwater
• Agent
• Facial feature, for some
• Treacherous spy
• Watch undercover
• Certain mole
• Seek intelligence
• Person with intelligence?
• Intelligence purveyor