Inexperienced fighter in protected area (5,4)
I believe the answer is:
green belt
'protected area' is the definition.
(I've seen this before)
'inexperienced fighter' is the wordplay.
'inexperienced' becomes 'green' (similar in meaning).
'fighter' becomes 'belt' (I am not sure about this - if you are sure you should believe this answer much more).
'green'+'belt'='GREEN BELT'
'in' acts as a link.
Can you help me to learn more?
(Other definitions for green belt that I've seen before include "can't be built on?" , "status of karate?" , "of restricted development?" , "Area round city with building restrictions" , "Protected land around city" .)