The most common and most likely answer to this crossword clue is the 4 plus 2 letter word SHUT IN
I've seen this crossword clue in The Daily Telegraph
S
H
U
T
I
N
Buddy explains!
The straight part
We know that "fenced off" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fenced off = shut in.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 SHUT IN mean?
SHUT IN noun- A person confined to a location, as by illness or infirmity.
- Confined to a location, as by infirmity or illness.