The most common and most likely answer to this crossword clue is the 10 letter word FORTRESSES
I've seen this crossword clue in Financial Times
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More clues leading to the result FORTRESSES
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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 FORTRESSES mean?
FORTRESSES noun- A fortified place; a large and permanent fortification, sometimes including a town; for example a fort, a castle; a stronghold; a place of defense or security.
- A position that, if obtained by the weaker side, will prevent penetration by the opposing side, generally achieving a draw.