Related Clues:

• "Not likely!"
• Doubter's reply
• Skeptic's challenge
• Skeptical reply
• Response of disbelief
• Disbeliever's comment
• 'Mmm hmm ...'
• 'Su-u-ure'
• "Fat chance"
• 'Doubtful'
• "Sure, whatever!"
• ''My eye!''
• 'Mmm hmm'
• "Dream on!"
• Doubting riposte