From Latin vita , which means life.
Outside of its own existence or source, life is only recognized through some form of expression or dynamic. A living organism experiences its own life from the internal dynamics of its own being, something not observable from outside - in the absence of an expression or dynamic.
Can there be vitality (life) with no expression or dynamic (internal or external)? By this definition the answer would need to be : "No."
In the context of urban planning, vitality refers to the capacity of a place to grow or develop its likeliness and level of economic activity.