Related Clues:

• That which is not done
• Unwise act
• Double denial
• 'That is completely the wrong way!'
• 'You've got it all wrong'
• Thing to avoid
• 'That's completely wrong!'
• Burping in public, e.g.
• Ill-advised move
• Off-limits act
• It just isn't done
• Non-starter
• Something proscribed
• Banned behavior
• Prohibited behavior