Related Clues:

• "Attention, please!"
• Ahem relative
• Horse-halting cry
• How about a call to slow down?
• Doctor, one that stops a horse
• How odd a call to stop
• Said to stop a horse
• Stop, Dobbin!
• Slow down!
• Stop! — steady on!
• "Hold on there!"
• "Not so quick, Silver!"
• Head-turning cry
• "Halt!"
• "Ahem" relative