A drink of benefit or interest (4)
I believe the answer is:
sake
I believe this is a triple definition!
'a drink' is the first definition.
(sake is a kind of drink)
'of' is a link.
'benefit' is the second definition.
(sake is a kind of benefit)
'or' acts as a link.
'interest' is the third definition.
(I know that interest can be written as sake)
(Other definitions for sake that I've seen before include "Japanese alcoholic drink make from rice" , "Benefit - behalf" , "Japanese spirit made from rice" , "Benefit - Japanese liquor" , "'Reason, purpose (4)'" .)