The most common and most likely answer to this crossword clue is the 11 letter word CONTINENTAL
I've seen this crossword clue in The Sunday Telegraph
C
O
N
T
I
N
E
N
T
A
L
More clues leading to the result CONTINENTAL
Buddy explains!

The straight part
We know that "European" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case european = continental.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does CONTINENTAL mean?
CONTINENTAL noun- Someone from the continent.
- A member of the Continental army.
- Paper scrip (paper money) issued by the continental congress, largely worthless by the end of the war.
- (by extension) The smallest amount; a whit; a jot.
- Of or relating to a continent or continents.
- Of the mainland, as opposed to an island offshore
- (chiefly in the UK) Relating to, or characteristic of, continental Europe
- Of or relating to the confederated colonies collectively, in the time of the Revolutionary War.