Start spending money, just for fun (5)
I believe the answer is:
'fun' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
'start spending money just' is the wordplay.
'start' suggests taking the first letters.
'money' becomes 'p'.
'just' becomes 'oof' (I can't explain this - if you can you should give a lot more credence to this answer).
The first letter of 'spending' is 's'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for spoof that I've seen before include "Take-off" , "Parody - prank" , "Satirical imitation" , "Parody - hoax" , "Parody - hoaxing game" .)