When fined, we hear, you just have to cough up (4)
I believe the answer is:
find
'cough up' is the definition.
The answer and definition can be both acts as well as being singular nouns.
Maybe you can see a link between them that I don't see?
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for find that I've seen before include "Locate or discover" , "Track down" , "Come across" , "Discover by chance" , "Acquisition" .)