The most common and most likely answer to this crossword clue is the 4 letter word NOSY
I've seen this crossword clue in The Daily Telegraph
N
O
S
Y
More clues leading to the result NOSY
- Curious figures — and one unknown
- Inquisitive father’s boy slipped up on study, finally
- Curious revolutionary poet's last letters
- NOSY
- Curious how system creates stem
- Curious final parts in addition to serious play
- Curious numbers close to infinity
- Boy going round yard snooping
- Boy reversing his conclusion — that’s curious
- Not easy without drink consumed? That’s curious
Buddy explains!

The straight part
We know that "snooping" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case snooping = nosy.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 NOSY mean?
NOSY noun- A look at something to satisfy one's curiosity.
- Prying, inquisitive or curious in other’s affairs; tending to snoop or meddle.
- Having a large or elongated nose.