A place to stop being vacant? (3)
I believe the answer is:
gap
'a place' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for gap that I've seen before include "Space (maybe for a year?)" , "A break in something continuous, like a hedge" , "Interval, break" , "Narrow space" , "Interval, space" .)