The most common and most likely answer to this crossword clue is the 5 letter word OFLAG
I've seen this crossword clue in The Times
O
F
L
A
G
More clues leading to the result OFLAG
- Old stone prison
- Camp belonging to prisoner?
- Golf courses surrounding a camp, not for men
- Nothing to salute in officers’ camp?
- Second in command meets ensign in prison camp
- No place for a captured ranker or aged gaolbird
- Camp has nothing standard
- Force stepping in over prisoner in camp
- POW camp housed in regal fortress overthrown
Buddy explains!

The straight part
We know that "Camp" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case camp = oflag.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 OFLAG mean?
OFLAG noun- A German prisoner-of-war camp for officers only.