Related Clues:

• Time server
• Pen pal?
• Climactic beginning?
• Like some debaters
• Not a pro
• Picketer, perhaps
• Prefix with proton or ballistic
• Prefix with hero or matter
• Negative prefix
• Opposing side
• One of the opposition
• Apt to say nay
• Lifer
• Opposed one
• One side of an issue