The most common and most likely answer to this crossword clue is the 1 plus 4 plus 5 plus 5 letter word A HARD DAY’S NIGHT
A
H
A
R
D
D
A
Y
â
€
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S
N
I
G
H
T
Buddy explains!

The straight part
We know that "Film" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case film = a hard day’s night.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.