The most common and most likely answer to this crossword clue is the 9 letter word PORBEAGLE
I've seen this crossword clue in Financial Times
P
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More clues leading to the result PORBEAGLE
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The straight part
We know that "Shark" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case shark = porbeagle.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 PORBEAGLE mean?
PORBEAGLE noun- A large pelagic predatory shark, Lamna nasus, of the Atlantic.