Related Clues:

• Good looker?
• Look in (on)
• Le Carré staple
• Watch secretly
• Finder of secrets
• Mole, maybe
• Not get off easily?
• Ferret out
• Try to open a jar, say
• Bug someone, e.g.
• Catch a glimpse of
• Stratego piece
• Crowbar
• Maxwell Smart, for one
• Watch covertly