Related Clues:

• Peck at
• Chivvy
• Worry persistently
• Horse
• Humble horse
• Tiresome sort
• Gripe constantly
• 'What, me ___?'
• No Derby contender
• Decrepit horse
• Xanthippe, e.g.
• Don't bet on it
• Pester repeatedly
• Gadfly
• Broken-down horse