Related Clues:

• One might be verbal
• Seizure
• Involuntary contraction
• First O of O-O-O
• First correct Hollywood Square
• Charley horse, e.g.
• Back ailment
• First X?
• First X or O?
• Convulsion
• Part of three-in-a-row
• Nervous habit
• Muscular jerk?
• Sudden spasm
• Quiver