The most common and most likely answer to this crossword clue is the 5 letter word EMPTY
I've seen this crossword clue in The Sunday Telegraph
E
M
P
T
Y
More clues leading to the result EMPTY
- Vain attempt you keep hidden
- My pet cuckoo is vain
- Sentry regularly maintaining redcap's a dead man
- English politician, vacant Tory with nothing inside
- Carrying no passengers regularly seems petty
- Attract topless lady, ultimately vain
- Meaningless passage from the MP, typically
- Quarter of Arabian Desert has space with Australian company
- Meaningless gesture’s ending with surprised exclamation? Little point in that
- Held in contempt, yob is vacant
Buddy explains!

The straight part
We know that "Vacant" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vacant = empty.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does EMPTY mean?
EMPTY noun- (usually plural) A container, especially a bottle, whose contents have been used up, leaving it empty.
- To make empty; to void; to remove the contents of.
- Of a river, duct, etc: to drain or flow toward an ultimate destination.
- Devoid of content; containing nothing or nobody; vacant.
- Containing no elements (as of a string, array, or set), opposed to being null (having no valid value).
- Free; clear; devoid; often with of.
- Having nothing to carry, emptyhanded; unburdened.
- Destitute of effect, sincerity, or sense; said of language.
- Unable to satisfy; hollow; vain.
- Destitute of reality, or real existence; unsubstantial.
- Destitute of, or lacking, sense, knowledge, or courtesy.
- (of some female animals, especially cows and sheep) Not pregnant; not producing offspring when expected to do so during the breeding season.
- Producing nothing; unfruitful; said of a plant or tree.