Related Clues:

• Not supporting
• Not for
• Less-than-climactic start?
• Lover's antithesis
• Hardly a fan
• The "A" of ABM
• Knock or social preceder
• Nay voter
• Prefix for freeze
• One who's against
• Intolerant sort
• Definitely not a pro
• Social starter?
• Side in an argument
• Misanthrope, e.g.