Related Clues:

• Suggestion
• Something the nose knows
• On the ___
• Bloodhound's guide
• Portent
• Unpleasant aura
• Handwriting on the wall
• Radon lacks it
• Preindication
• Nostril wrinkler
• Foreshadow
• A shoe may have one
• Methane's lack
• Straw in the wind
• Java waft