Best fruit for boss (3,6)
I believe the answer is:
top banana
'boss' is the definition.
(top banana means a boss or leader)
'best fruit' is the wordplay.
'best' becomes 'top' (top can mean the very best).
'fruit' becomes 'banana' (type of fruit).
'top'+'banana'='TOP BANANA'
'for' acts as a link.
(Other definitions for top banana that I've seen before include "leader" , "Big cheese" , "figurehead?" , "Star comedian" , "Most important person in group (informal)" .)