The most common and most likely answer to this crossword clue is the 10 letter word CASABLANCA
C
A
S
A
B
L
A
N
C
A
More clues leading to the result CASABLANCA
- Cabals can corrupt a port
- How Buñuel may have interpreted White House film?
- Film that’s translated into English for White House
- Film cast able, without feet, to dance naked!
- In Bergman film taxi crosses a small canal, exotic
- Film about graduates recalling construction of canal
- Picture bean counters with a black car taking one out
- Film taxi crossing a small choppy canal
- A sign of emptiness largely in conspirator in film
- Film when in taxi winding canal
Buddy explains!

The straight part
We know that "port" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case port = casablanca.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.