Related Clues:

• Uncontrolled contraction
• Hose problem
• Foible
• First of three in a pencil/paper game
• Rare find
• It could be represented by an "X"
• Quirkiness
• Persistent personal quirk
• ___-tac-toe
• First O?
• Unexpected wrinkle
• Flaw in the system
• Quirky behavior
• The first O of O-O-O
• One might be verbal