Decline, then European means to raise standard (8)
I believe the answer is:
flagpole
'means to raise standard' is the definition.
(I've seen this before)
'decline then european' is the wordplay.
'decline' becomes 'flag'.
'then' says to put letters next to each other.
'european' becomes 'pole' (someone from Poland).
'flag'+'pole'='FLAGPOLE'
(Other definitions for flagpole that I've seen before include "Mast on which banner is hoist" , "On which standard flies" , "Ceremonial mast" , "Pin" , "Support for banner." .)