Son taking in crops is doing the wrong thing (7)
I believe the answer is:
sinning
'wrong thing' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'son taking in crops is doing' is the wordplay.
I cannot quite see how this works, but
'son' could be 's' (genealogical abbreviation for son) and 's' is located in the answer.
'in' is found in the answer.
This may be the basis of clue (or it may be nonsense).
'the' is the link.
Can you help me to learn more?
(Another definition for sinning that I've seen is " Doing badly".)