The most common and most likely answer to this crossword clue is the 3 letter word EVA
E
V
A
Buddy explains!

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 EVA mean?
EVA adverb- Always, frequently, forever.
- Continuously, constantly, all the time (for the complete duration).
- At any time.
- In any way.
- As intensifier following an interrogative word.