A way to earn extra money in court (8)
I believe the answer is:
sideline
'money in court' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'a way to earn extra' is the wordplay.
'a way' becomes 'line' (line is a kind of way).
'to' says to put letters next to each other (I've seen this in other clues).
'earn extra' becomes 'side' (I am not sure about this - if you are sure you should believe this answer much more).
'line' put after 'side' is 'SIDELINE'.
Can you help me to learn more?
(Other definitions for sideline that I've seen before include "Boundary marker" , "Take out of the picture" , "hobby" , "subsidiary source of income" , "Spare-time activity" .)