The most common and most likely answer to this crossword clue is the 10 letter word CHAUVINISM
I've seen this crossword clue in The Daily Telegraph
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The straight part
We know that "fanatical pride" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fanatical pride = chauvinism.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.
What does CHAUVINISM mean?
CHAUVINISM noun- Excessive patriotism, eagerness for national superiority; jingoism.
- Unwarranted bias, favoritism, or devotion to one's own particular group, cause, or idea.