Possible Clues:

• Sentence that appears to contradict itself
• Hell's Angels, e.g.
• Original copies, e.g.
• Clearly confused, e.g.
• 'Figure of speech, it contains contradictory terms (8)'
• Phrase or sentence with inherent contradiction
• Microsoft Works, according to some
• Alone together, e.g.
• Elevated subway, e.g.
• Element in "Night of the Living Dead"