Related Clues:

• 'Nuts!'
• Emphatic denial
• 'Yeah, right!'
• 'Phooey!'
• 'That's a lie!'
• Slangy refusal
• Haughty refusal
• 'Darn!'
• Cynic's retort
• 'When pigs fly!'
• See 50-Across
• 'Forget it!'
• 'Don't think so'
• Scrooge's cry
• Not at all