Get most of the money back in Japan! (3)
I believe the answer is:
yen
'get' is the definition.
Although both the answer and definition are verbs in their base form, I don't see how they can define each other.
'most of the money back in japan' is the wordplay.
'most of the money' becomes 'ye' (I can't explain this - if you can you should believe this answer much more).
'back in' indicates one should take the final letters (the 'back' of the word).
The final letter of 'japan' is 'n'.
'ye'+'n'='YEN'
Can you help me to learn more?
(Other definitions for yen that I've seen before include "Intense desire for Japanese money" , "Long for Japanese money?" , "Currency of Japan" , "Japanese currency; yearning" , "Pine" .)