Apple mountain (4)
I believe the answer is:
fuji
I believe this clue is a double definition.
'apple' is the first definition.
(type of apple)
'mountain' is the second definition.
(I have seen 'Japanese mountain ' mean 'fuji' so perhaps 'mountain' could also mean 'fuji')
(Other definitions for fuji that I've seen before include "Japanese mount" , "Sacred volcano of Japan" , "Japanese holy mountain" , "Extinct volcano is the highest peak in Japan" , "Japan's sacred mountain" .)