Related Clues:

• First 'O'?
• Fixation
• Red hair or freckles
• Shortcoming
• X or O, in a game
• One may be expressed by a gene
• Brown eyes or blond hair, e.g.
• Uncontrollable movement
• Habitual jerk
• Hair color, for example
• Essential quality
• Stubbornness or kindliness, e.g.
• Brown eyes or baldness, e.g.
• Colorblindness, e.g.
• Roman nose, e.g.