The most common and most likely answer to this crossword clue is the 11 letter word SYMPATHISER
I've seen this crossword clue in The Daily Telegraph
S
Y
M
P
A
T
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I
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More clues leading to the result SYMPATHISER
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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 SYMPATHISER mean?
SYMPATHISER noun- A person who sympathizes (with a political cause, a side in a conflict, etc.); a supporter.
- A person who has, shows or expresses sympathy (with another person or people); a person who enters into the feelings of another.