Related Clues:

• Galileo, for one
• Inquisition target
• Nonconformist
• Freethinker, perhaps
• Freethinker
• Nonbeliever
• Doctrine doubter
• Non-believer
• Inquisitor's quarry
• Unbeliever
• Excommunication candidate
• Inquisition victim
• Luther was one
• Oscar Wilde or Bill Maher, for example
• One seriously straying from the flock?