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