The most common and most likely answer to this crossword clue is the 4 letter word ZING
I've seen this crossword clue in The Times
Z
I
N
G
More clues leading to the result ZING
- Vitality unknown in Grantchester at first
- Vivacity of Zulu monarch’s beginning to go
- Pep included by name in two columns today
- Go drinking; no disapproval heard
- Go drinking alcohol without a cry of disapproval
- Having a nap, losing party spirit
- Go drinking, shrugging off adverse reaction
- Go free from Baltic?
- A graduate fired by incredible energy
Buddy explains!

The straight part
We know that "Vitality" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case vitality = zing.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 ZING mean?
ZING noun- A short high-pitched humming sound, such as that made by a bullet or vibrating string.
- A witty insult or derogatory remark.
- Zest or vitality.
- Pleasant or exciting flavour of food.
- To move very quickly, especially while making a high-pitched hum.
- A high pitched humming sound.
- Used to acknowledge a witty comeback, a zinger.