Very long European film (4)
I believe the answer is:
epic
'very long' is the definition.
(I've seen this before)
'european film' is the wordplay.
'european' becomes 'e' (abbreviation e.g. EU).
'film' becomes 'pic' (I've seen this in other clues**).
'e'+'pic'='EPIC'
(Other definitions for epic that I've seen before include "(Of) immense (proportions)" , "Blown up" , "great film" , "Heroic, huge" , "Long classic film" .)