Creative impulse of a female, calm American (8)
I believe the answer is:
afflatus
'creative impulse' is the definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'a female calm american' is the wordplay.
'female' becomes 'f' (common abbreviation).
'calm american' becomes 'flatus' (I can't explain this - if you can you should give a lot more credence to this answer).
'a'+'f'+'flatus'='AFFLATUS'
'of' is the link.
Can you help me to learn more?
(Other definitions for afflatus that I've seen before include "inspiration" , "Poet's creative impulse" .)