Related Clues:

• "Ain't gonna happen!"
• "Over my dead body!"
• "Guess again"
• 'That's false'
• Defensive denial
• "Nuh-uh"
• Indignant denial
• "Guess again!"
• 'Au contraire'
• "Nah!"
• "Incorrect!"
• Terse negative
• "Absolutely not!"
• "You're dreaming"
• Slangy denial, and a hint to 20-, 29-, 46- and 56-Across