Related Clues:

• Having pricked ears
• Aware of, as a hoax
• Keen-eyed
• Like watchmen
• Up on the latest trends
• More than just suspicious of
• Paying attention
• Knowledgeable
• Clued in about
• Not snowed by
• Able to see through
• Like sentries
• Oft-replaced part
• Endowed with feeling
• Like an excellent guard dog