Vacancy.

Yeh, I've slacked off quite a bit on this. And I don't really think you want to read a ghost's ramblings, but alas, you still stick around, do you not?

Vacancy. 

noun, plural vacancies.
1.
the state of being vacant; emptiness.

So, what's the origin? 

'Tis Latin:

"state of being vacant," from Late Latin vacantia

and

Latin vacans "empty, unoccupied"

But what about vacuity?

"hollow space," from Latin vacuitas 

"empty space, emptiness, absence, vacancy, freedom," from vacuus

Vacancy, to me, is almost a state of mind. It's completely empty. You used to have information and creativity, and thoughts that would fill the space; almost like happiness. Then it goes away. It becomes vacant. 

Everything goes away and there's just a void. 

Vacancy of the heart and mind.