Related Clues:

• McCoy, to Hatfield
• No ally
• Formal outfit
• Face covering
• Mailman, to a canine?
• 'This is a Montague, our ___': 'Romeo and Juliet'
• The Joker, to Batman
• Prom attire, briefly
• Quantity of bricks
• Formal buy, informally
• Face mask?
• One to beat
• Formalwear, informally
• Moriarty, to Holmes
• Guarantees a pension