Related Clues:

• ''Nah!''
• "Forget it"
• See 19 Across
• ''Nope!''
• "Out of the question!"
• Informal refusal
• ''Don't hold your breath!''
• On the 31st of February
• ''Not a chance!''
• Informal turndown
• 'No way, no how!'
• 'Never gonna happen'
• 'Not on your life!'
• 'When hell freezes over'
• Under no conditions