Related Clues:

• 'That's a ___!'
• Test-___ treaty
• Improper
• Bête noire
• Prohibit
• Talking during a film, e.g.
• Thou-shalt-not
• Put an end to
• Outlaw
• Blackout
• Rule out
• Forbidden fruit
• Bar
• Interdict
• Put the kibosh on