Related Clues:

• 'You suck!'
• Stands complaint
• Boo accompanier
• Respond to a bad call, maybe
• This might follow a bad pun
• Theater jeer
• Word to a villain
• Shout to a hiccuper
• Bad sound at a campaign rally
• Disagree with a call, perhaps
• [That's an old one!]
• Boo companion
• Cause of a scare
• Ghost line
• See 24 Across