Possible Clues:

• "Not gonna happen!"
• Show agreement with reserve? Absolutely not
• Refusal to play
• With a void in diamonds, diamonds elicit a negative response
• 'Not happening'
• 'Ixnay!'
• I shan't play!
• 'Fuhgeddaboudit!'
• Refusal or agreement to be seen with top off?
• 'Uh-uh!'