The most common and most likely answer to this crossword clue is the 5 plus 4 letter word GREEN BELT
I've seen this crossword clue in Financial Times
G
R
E
E
N
B
E
L
T
More clues leading to the result GREEN BELT
- Judo grade that can’t be improved upon?
- Where housing’s lacking, inexperienced run fast
- Devotee of martial arts field is protected here
- Young earl in Sandwich area under protection
- Fourth grade judo award which will not attract development
- Martial arts exponent‘s area that’s protected
- Area in which there may be no developments?
- Martial arts student, inexperienced, given punch
- Level of martial arts skill / that can’t be developed outside city
- Place for putting punch -- vulnerable area that needs protection
Buddy explains!
The straight part
We know that "Devotee of martial arts/field is protected here" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case devotee of martial arts/field is protected here = green belt.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.