Related Clues:

• Look through a peephole, perhaps
• Watch from the trees, say
• "I ___" (early Cosby show)
• World traveler, perhaps
• Intel collector
• Concern yourself with intelligence
• "The ___ Who Loved Me"
• Code user
• Keep under surveillance
• Secret stealer
• Le Carré hero, e.g.
• Hari or Harriet
• Watch in secret
• KGB worker
• Enemy agent