Related Clues:

• 'Don't think so!'
• Opposite of 15-Across
• "Fat chance!"
• Inaccurate
• "Don't think so"
• 'Unh-unh'
• "I don't think so!"
• No, informally
• "That's a lie!"
• 'Ixnay'
• "Not on your life!"
• 'Forget about it!'
• "Uh-uh!"
• 'Au contraire!'
• Relaxed rejection