The most common and most likely answer to this crossword clue is the 10 letter word SEGREGATED
I've seen this crossword clue in Financial Times
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More clues leading to the result SEGREGATED
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The straight part
We know that "Isolated" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case isolated = segregated.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 SEGREGATED mean?
SEGREGATED verb- To separate, especially by social policies that directly or indirectly keep races or ethnic groups apart.
- (of a person or thing) Separated or isolated from others, or from another group.
- (of an institution) Having access restricted to certain groups, or excluding certain groups.