Possible Clues:

• Attribute loss of soldiers to fifth columnist
• It may be dominant
• Shade or false?
• Characteristic cunning overturned it
• Hair color, e.g.
• It may be passed down the line
• Attribute, characteristic
• Having the knack of lifting it: an idiosyncrasy
• It's characteristic and that's flat, by the sound of it
• Characteristic of the flat, by the sound of it