Related Clues:

• Obsession
• Muscle twitch
• Habit, of a sort
• Odd mannerism
• Sudden movement
• One-third of a child's game
• Muscular contraction
• ''Hollywood Squares'' square
• 'A Nervous ___ Motion of the Head to the Left' (Andrew Bird song)
• Quirky trait
• __-tac-toe
• First of a game trio
• First X or O
• First O
• Odd habit