Related Clues:

• He's up against it
• Knock opener?
• Opposing opinion
• Prefix with nuclear or freeze
• Prefix for social
• Part of NSAID
• Prefix for inflammatory
• Mitigating prefix
• One who objects
• 'Nay' sayer
• Proposal opponent
• Prefix with ''body'' or ''corrosion''
• Knock intro
• Sure to vote against
• Negative voter