Possible Clues:

• Liable to unpredictable change
• Random, unreliable
• Uneven in movement or quality
• Unreliable ruler, scoundrel in charge
• Unreliable dodgy criteria I ignored
• Irregular or uneven in movement or habits
• Rat at heart, Eric is inconsistent
• Irregular in motion or habit
• Lacking consistency
• Irregular in habit or movement