Enemy following old European (3)

I believe the answer is:

foe

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'enemy' is the definition.
(synonyms)

'following old european' is the wordplay.
'following' is a charade indicator (letters next to each other).
'old' becomes 'fo' (I can't justify this - if you can you should believe this answer much more).
'european' becomes 'E' (abbreviation e.g. EU).
'fo' put next to 'e' is 'FOE'.

Can you help me to learn more?

(Other definitions for foe that I've seen before include "friend never!" , "Adversary" , "Evil rival" , "Am archaic enemy" , "Someone opposing" .)

I've seen this clue in The Sun.

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