In the end, delve about in (6)
I believe the answer is:
'in the end delve about in' is the definition.
I can't judge whether this defines the answer.
'delve about in' is the wordplay.
'delve' becomes 'fish' (I can't justify this - if you can you should give a lot more credence to this answer).
'about' is an insertion indicator.
'fish' placed around 'in' is 'FINISH'.
Can you help me to learn more?
(Other definitions for finish that I've seen before include "Refinement in social graces" , "perfection" , "Conclude, stop" , "Pefect" , "Treatment of surface" .)