Effusion a girl talked of before race (9)
I believe the answer is:
emanation
'effusion' is the definition.
(both can mean an emission or outpouring)
'before race' is the wordplay.
'before' becomes 'ema' (I am not sure about this - if you are sure you should believe this answer much more).
'race' becomes 'nation' (both can mean a national or ethnic group).
'ema'+'nation'='EMANATION'
'a girl talked of' acts as a link.
This may not be correct. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for emanation that I've seen before include "Something flowing out from a source" , "Something produced from a source" , "discharge" , "produce radioactive gas" , "Pouring out" .)