Related Clues:

• Retort to "It ain't so!"
• Puerile retort
• ''This porridge __ hot!''
• Greta Thunberg book 'No One ___ Small to Make a Difference'
• 'Are not!' reply
• "Not so!" retort
• "Not so!" response
• Reply to "Nuh-uh!"
• Response to "Are not!"