Related Clues:

• Double-dealer
• Jailhouse singer?
• "The Wind in the Willows" fellow
• Lab animal
• Blockage remover
• Betrayer
• Blow the whistle (on)
• Ben, in a film
• Deceitful sort
• Name names
• Lab critter
• Grass inhabitant?
• Mob pariah
• Coral, for one
• Arnold or Judas, e.g.