Very best stuff intercepted by European (5)
I believe the answer is:
cream
'very best' is the definition.
(I've seen this before)
'stuff intercepted by european' is the wordplay.
'stuff' becomes 'cram' (synonyms).
'intercepted by' is an insertion indicator (I've seen this in other clues).
'european' becomes 'E' (abbreviation e.g. EU).
'cram' placed around 'e' is 'CREAM'.
(Other definitions for cream that I've seen before include "Beat" , "Elite; colour" , "'There are more ways of killing a cat than choking it with ....." , "best people" , "Thick milk" .)