Related Clues:

• Forbidden fruit
• Proscription
• Double negative?
• Naughty deed
• Forbidden thing
• Failed attempt
• Aborted mission words
• Unworkable
• Mission cancellation
• Prohibition
• Jaywalking, e.g.
• NASA cancellation
• 'Fuhgeddaboudit!'
• Inadvisable action
• Rule breaker