Fancy man may gush about a pile-driver (8)
I believe the answer is:
paramour
'fancy man' is the definition.
(synonyms)
'gush about a pile-driver' is the wordplay.
'gush' becomes 'pour' (I've seen this in another clue).
'about' means one lot of letters goes inside another.
'a pile driver' becomes 'aram' (I can't justify this - if you can you should give a lot more credence to this answer).
'pour' going around 'aram' is 'PARAMOUR'.
'may' acts as a link.
Can you help me to learn more?
(Other definitions for paramour that I've seen before include "wife's toy boy, for example" , "Lover, especially of a married person" , "Kept woman" , "courtesan" , "Mistress, lover" .)