Related Clues:

• ''As if!''
• Word before and after say
• "Forget it!"
• ''No way!''
• Strong denial
• ''When donkeys fly!''
• See 19 Across
• ''Don't hold your breath!''
• On the 31st of February
• ''Not a chance!''
• 'No way, no how!'
• 'Not on your life!'
• 'When hell freezes over'
• Under no conditions
• Rebel yell