Great European covers up (6)
I believe the answer is:
superb
'great' is the definition.
(I've seen this before)
'european covers up' is the wordplay.
'european' becomes 'serb' (person from Serbia).
'covers' means one lot of letters goes inside another.
'serb' going around 'up' is 'SUPERB'.
(Other definitions for superb that I've seen before include "Really excellent, brilliant" , "Quite splendid, really excellent" , "Of surpassing excellence" , "Outstandingly excellent" , "First-rate" .)