Cultured European press boss (8)
I believe the answer is:
polished
'cultured' is the definition.
(synonyms)
'european press boss' is the wordplay.
'european' becomes 'Polish ' (Poland is in Europe).
'press boss' becomes 'ed' (I've seen this in other clues).
'polish'+'ed'='POLISHED'
(Other definitions for polished that I've seen before include "Shining or refined" , "Made shiny and smooth" , "Buffed to a shine" , "Highly accomplished" , "Difference, statistical quantity" .)