Related Clues:

• Power or vigour.
• Capacity for action
• Power or vigorous activity
• Vigour or power
• Vigour, animation
• Capacity for activity
• Vigour, power
• Get-up-and-go, vitality
• Vigour, vitality
• Vigour, vim, vitality
• Healthy capacity for vigorous activity
• Exertion of force
• It's measured in joules
• Informal intellectual of ovoid type
• It's measured in joules or ergs