European national entering sneakily, a day earlier (11)

I believe the answer is:

montenegrin

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'european' is the definition.
(I've seen this before)

'entering sneakily a day earlier' is the wordplay.
'sneakily' is an anagram indicator (a tricksy or sneaky ordering of the letters).
'a day' becomes 'mon' (abbreviation for Monday).
'earlier' is a charade indicator (letters next to each other).
'entering' is an anagram of 'tenegrin'.
'tenegrin' put after 'mon' is 'MONTENEGRIN'.

'national' is the link.
I am not very happy about this link. It may belong to another bit of the clue.

Can you help me to learn more?

(Another definition for montenegrin that I've seen is " European".)

I've seen this clue in The Times.

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